jquery2.0.3源码及解析

jquery2.0.3源码附注释

/*!

 * jQuery JavaScript Library v2.0.3
 * http://jquery.com/
 *
 * Includes Sizzle.js
 * http://sizzlejs.com/
 *
 * Copyright 2005, 2013 jQuery Foundation, Inc. and other contributors
 * Released under the MIT license
 * http://jquery.org/license
 *
 * Date: 2013-07-03T13:30Z
 */
 //匿名函数,(function(){})()叫做匿名函数自执行,防止冲突。undefined我们在传参的时候任意指定的,它就是一个属性
(function( window, undefined ) {

// Can't do this because several apps including ASP.NET trace
// the stack via arguments.caller.callee and Firefox dies if
// you try to trace through "use strict" call chains. (#13335)
// Support: Firefox 18+
//"use strict";
var
    // A central reference to the root jQuery(document)它和$、jquery是一样的,只是目前我们还没出现$\jquery的定义而已,rootjQuery=$(document)
    rootjQuery,

    // The deferred(延迟) used on DOM ready
    readyList,//延迟列表

    // Support: IE9
    // For `typeof xmlNode.method` instead of `xmlNode.method !== undefined`,我们得到一个字符串形式的undefined  typeof undefined="undefined"
    core_strundefined = typeof undefined,

    // Use the correct document accordingly with window argument (sandbox),window下的变量存储,其实不存储我们也是直接拿过来就可以用的,但是就是有利于压缩的情况
    location = window.location,
    document = window.document,
    //存的就是html标签  var doc=document.documentElement; doc.lastChild;doc.childNodes[0].nodeName
    docElem = document.documentElement,

    // Map over jQuery in case of overwrite,下面2个都是防止命名冲突,在jQuery初始化的时候保存了外部的$和jQuery
    _jQuery = window.jQuery,

    // Map over the $ in case of overwrite
    _$ = window.$,

    // [[Class]] -> type pairs,使用$.type()时候用到,class2type={'[Object String]':'string','[Object Array]':'array'}
    class2type = {},

    // List of deleted data cache ids, so we can reuse them,以前版本和缓存数据是有关的,but从现在开始已经没什么用处了,just a 空数组
    core_deletedIds = [],

    core_version = "2.0.3",

    // Save a reference to some core methods,数组的一些操作,方便压缩和后续处理
    core_concat = core_deletedIds.concat,
    core_push = core_deletedIds.push,
    core_slice = core_deletedIds.slice,
    core_indexOf = core_deletedIds.indexOf,
    core_toString = class2type.toString,
    core_hasOwn = class2type.hasOwnProperty,
    core_trim = core_version.trim,

    // Define a local copy of jQuery(局部的,window.jQuery = window.$ = jQuery;使其对外了)
    jQuery = function( selector, context ) {


        // The jQuery object is actually just the init constructor 'enhanced'(Jquery.fn.init是这里的构造函数),jQuery.fn就是jQuery的原型,则下面这个语句就是让我们的jquery.prototype下去找init方法
        //这样做的原因主要是和传统的方法比较的,它可以让我们不必手动去先进行初始化操作,直接就初始化了,对于我们调用后续的方法是非常便利的。
        return new jQuery.fn.init( selector, context, rootjQuery );
    },

    // Used for matching numbers,查找匹配数字
    core_pnum = /[+-]?(?:\d*\.|)\d+(?:[eE][+-]?\d+|)/.source,

    // Used for splitting on whitespace,匹配单词的
    core_rnotwhite = /\S+/g,

    // A simple way to check for HTML strings
    // Prioritize #id over <tag> to avoid XSS via location.hash (#9521)
    // Strict HTML recognition (#11290: must start with <)
    //匹配标签|id
    rquickExpr = /^(?:\s*(<[\w\W]+>)[^>]*|#([\w-]*))$/,

    // Match a standalone tag(匹配单标签,例如,<p></p>或者<div></div>)
    rsingleTag = /^<(\w+)\s*\/?>(?:<\/\1>|)$/,

    // Matches dashed string for camelizing(IE前缀)
    rmsPrefix = /^-ms-/,
    rdashAlpha = /-([\da-z])/gi,//-加上字母或数字的组合转大写,数字虽然不能转为大写,但是可以把-去掉

    // Used by jQuery.camelCase as callback to replace()(驼峰命名)
    fcamelCase = function( all, letter ) {
        return letter.toUpperCase();
    },

    // The ready event handler and self cleanup method(DOM加载完成后执行相应操作)
    completed = function() {
        //load事件:页面资源全部载入(JS/CSS/图片等全部加载完)触发
        //ready事件:原生无ready事件,只有DOMContentLoaded事件。jQuery中的ready事件为,当DOM加载完成触发,此时引用的资源未必已加载完成。
        //
        document.removeEventListener( "DOMContentLoaded", completed, false );
        window.removeEventListener( "load", completed, false );
        jQuery.ready();
    };

jQuery.fn = jQuery.prototype = {
    // The current version of jQuery being used,jQuery的版本
    jquery: core_version,

    constructor: jQuery,//修正指向 不写这个的话, constructor会指向Object,因此你重写了JQuery的prototype。
    /*
    //新建一个构造函数时,会自动在构造函数的prototype对象中新添constructor属性(指向构造函数)。
    但是为了防止原型对象的覆盖,比如:Person.prototype = {};这时里面的constructor指向会出问题,
    需要修正,Person.prototype = { constructor: Person}
    */
    init: function( selector, context, rootjQuery ) {
        var match, elem;

        // HANDLE: $(""), $(null), $(undefined), $(false),这些都是不正确的选择器
        if ( !selector ) {
            //直接返回,则程序不会往下执行了
            return this;
        }

        // Handle HTML strings($('#div1'),$('.box'),$('div'),$('#div1 div.box'),$('<li>'),$('<li></li>'))
        if ( typeof selector === "string" ) {
            if ( selector.charAt(0) === "<" && selector.charAt( selector.length - 1 ) === ">" && selector.length >= 3 ) {
                // Assume that strings that start and end with <> are HTML and skip the regex check
                /*
                // $("<li>") ->   match = [ null, "<li>", null ];
        // $("<li>1</li><li>2</li>") ->   match = [ null, "<li>1</li><li>2</li>", null ];
                *//设定不同类型的选择器所对应的match是不同的,这样才能方便后续处理。
                match = [ null, selector, null ];

            } else {
                /*
                match=null //$('.box')
                match=['#div1',null,'div1'] //$('#div1')
                match=['<li>hello','<li>',null]  //$('<li>hello')

                //   此正则rquickExpr匹配后,会出现以下几种情况:

        // 1. match = null; $(".box"), $("div"), $("#div1 div.box")

        // 2. match = ["#div1",null,"div1"];  $("#div1")

        // 3. match = ["<li>aaa","<li>",null]; $("<li>aaa")
                */
                match = rquickExpr.exec( selector );
            }

            // Match html or make sure no context is specified for #id(匹配创建标签或者是id(后面的指的是id))
            // $("#div1")通过id匹配元素,是在document中执行,不会传入context,所以context为空,因此进入if语句
            if ( match && (match[1] || !context) ) {

                // HANDLE: $(html) -> $(array)
                if ( match[1] ) {//则说明是match=['<li>hello','<li>',null]  //$('<li>hello')这种情况  // $("<li>"), $("<li>aaa"),$("<li>1</li><li>2</li>")
                    /*
                    true对应于$('<li>',$(document)),这样context[0]就是取得document
                    false对应于$('<li>',document),这样context就是取得document
                    所以想得到的就是document

                    //context就是document,因为创建元素只能在document中执行。但是页面里面有iframe时,iframe中的document与页面的document不同,所以$("<li>",document)有第二个参数。一般用不上。
                    */
                    context = context instanceof jQuery ? context[0] : context;
                    //$("<li>",$(document)),得到原生的document。

                    // scripts is true for back-compat
                    //jQuery.parseHTML返回的是数组,经历过merge操作后则返回的是json数据
                    /*
                    //parseHTML方法:第一个参数传入标签字符串"<li>",第二个参数传入执行上下文document,第三个参数true代表可以新建script标签"<script><\/script>"(script前面的反斜杠需要转义,其他标签不需要),false代表不能。返回值是一个数组:$("<li>") ->   ["li"],  $("<li>1</li><li>2</li>") ->["li","li"]

          //merge方法是把数组转换成jQuery对象:["li"] ->  {0:"li",length:1} ;["li","li"]   ->  {0:"li",1:"li",length:2}

          rsingleTag匹配单标签的,$("<li>"),$("<li></li>")
                    */
                    jQuery.merge( this, jQuery.parseHTML(
                        match[1],
                        context && context.nodeType ? context.ownerDocument || context : document,
                        true
                    ) );

                    // HANDLE: $(html, props)(处理单标签,多标签的话是不能进入到这个分支的例如:$('<li></li>',{title:'hi',html:'abcd'}).appendTo('ul');)
                    if ( rsingleTag.test( match[1] ) && jQuery.isPlainObject( context ) ) {
                        //$("<li>",{title:"hi",html:"abcd"})  针对这种情况的,context 为json对象
                        for ( match in context ) {
                            // Properties of context are called as methods if possible,处理html:'abcd'
                            if ( jQuery.isFunction( this[ match ] ) ) {//如果属性是jQuery方法,就执行方法
                                this[ match ]( context[ match ] );

                            // ...and otherwise set as attributes
                            } else {//处理title:'hi'
                                this.attr( match, context[ match ] ); //如果不是方法,就设置属性。
                            }
                        }
                    }

                    return this;

                // HANDLE: $(#id),处理id的情况
                } else {
                    elem = document.getElementById( match[2] );

                    // Check parentNode to catch when Blackberry 4.6 returns
                    // nodes that are no longer in the document #6963
                    // Blackberry 4.6:elem存在,但是页面上没有,所以添加了elem.parentNode,如果都满足,则elem一定存在页面上。
                    if ( elem && elem.parentNode ) {
                        // Inject the element directly into the jQuery object
                        this.length = 1;
                        this[0] = elem;
                    }

                    this.context = document;
                    this.selector = selector;
                    return this;
                }

            // HANDLE: $(expr, $(...))
            } else if ( !context || context.jquery ) {//find方法实际上调用的是sizzle(处理更复杂的选择器)
                return ( context || rootjQuery ).find( selector );
                //rootjQuery  = $(document)

        // 处理这种$(expr, context),context是否是jQuery对象(context.jquery存在就是jQuery对象),会转换成$(context).find(expr)

        //或者$(expr),会转换成$(document).find(expr)

            // HANDLE: $(expr, context)
            // (which is just equivalent to: $(context).find(expr)
            } else {//如果context存在,但是不是jQuery对象,就执行
                return this.constructor( context ).find( selector );//新建jQuery对象,并调用find方法
            }

        // HANDLE: $(DOMElement)($(this),$(document),$(DOMElement)将DOM对象转化为伪数组返回即可 
        } else if ( selector.nodeType ) {//如果是dom节点,比如:$(document) 
              //节点没有所谓的父级,所以它的执行上下文就是自己本身
            this.context = this[0] = selector;
            this.length = 1;
            return this;

        // HANDLE: $(function),$(function)等同于jQuery.ready(function)
        // Shortcut for document ready(传函数进行处理$(function(){}))
        } else if ( jQuery.isFunction( selector ) ) {//文档加载有两种方式:$(function(){}); $(document).ready(function(){});
            return rootjQuery.ready( selector );
        }
        //HANDLE: $($...),$($...)将参数执行结果(也是一个jQuery实例)包装到this上返回
    //因为$('#div1')或者是$($('#div1')),所以要验证selector是不是对象形式的。
        if ( selector.selector !== undefined ) {//$($("#div1")),当传入jQuery对象时
            this.selector = selector.selector;
            this.context = selector.context;
        }
    //传数组,传json的形式($([]),$({}))
    //makeArray把selector(类数组)转换成数组(外部使用),当传入第二个参数时(内部使用),就会转换成jQuery对象的形式。
        return jQuery.makeArray( selector, this );
    },

    // Start with an empty selector
    selector: "",

    // The default length of a jQuery object is 0
    length: 0, //匹配到的元素的长度,默认为0.

    toArray: function() {
        //如果不传参的话就会截取全部的
        return core_slice.call( this );
    },

    // Get the Nth element in the matched element set OR
    // Get the whole matched element set as a clean array
    //转原生集合,//获取当前集合中某一个或是全部的元素,需要注意的是,这里返回的是DOM节点对象,非jQuery对象,可不能再链式调用了。
    get: function( num ) {
        return num == null ?

            // Return a 'clean' array
            //截取全部的元素
            this.toArray() :

            // Return just the object
            //this[ num ]是对应的json找对应的属性,所以[]不是下标,而是找对应属性的情况
            ( num < 0 ? this[ this.length + num ] : this[ num ] );
    },

    // Take an array of elements and push it onto the stack
    // (returning the new matched element set)
    pushStack: function( elems ) {

        // Build a new jQuery matched element set  this.constructor()是空的jQUERY对象,神马都没有,merge实现数组或者json的合并
        var ret = jQuery.merge( this.constructor(), elems );

        // Add the old object onto the stack (as a reference)
        //要把之前的对象存储一下,ret应该是将要压入栈的元素
        ret.prevObject = this;
        //对执行上下文进行处理,执行上下文是都没有发生变化的
        ret.context = this.context;

        // Return the newly-formed element set
        return ret;
    },

    // Execute a callback for every element in the matched set.
    // (You can seed the arguments with an array of args, but this is
    // only used internally.)
    each: function( callback, args ) {
        return jQuery.each( this, callback, args );
    },

    ready: function( fn ) {
        // Add the callback
        jQuery.ready.promise().done( fn );

        return this;
    },

    slice: function() {
        return this.pushStack( core_slice.apply( this, arguments ) );
    },

    first: function() {
        return this.eq( 0 );
    },

    last: function() {
        return this.eq( -1 );
    },

    eq: function( i ) {
        var len = this.length,
            j = +i + ( i < 0 ? len : 0 );
        return this.pushStack( j >= 0 && j < len ? [ this[j] ] : [] );
    },

    map: function( callback ) {
        //进行二次处理
        return this.pushStack( jQuery.map(this, function( elem, i ) {
            return callback.call( elem, i, elem );
        }));
    },

    end: function() {//回溯到当前栈顶的上一级
        //回溯到最顶端,当回溯回溯没有了的时候(没有可回溯的对象了),那就变成空了
        return this.prevObject || this.constructor(null);
    },

    // For internal use only.
    // Behaves like an Array's method, not like a jQuery method.
    push: core_push,
    sort: [].sort,
    splice: [].splice
};

/*
jQuery的伪类选择函数
jQuery.fn.eq(函数用于获取当前jQuery对象所匹配的元素中指定索引的元素,并返回封装该元素的jQuery对象)

  jQuery.fn.first(函数用于获取当前jQuery对象所匹配的元素中的第一个元素,并返回封装该元素的jQuery对象)

  jQuery.fn.last(函数用于获取当前jQuery对象所匹配的元素中的最后一个元素,并返回封装该元素的jQuery对象)

  jQuery.fn.slice(函数用于选取匹配元素中一段连续的元素,并以jQuery对象的形式返回)

  jQuery.fn.map(函数用于处理当前jQuery对象匹配的所有元素,并将处理结果封装为新的数组。返回封装该数组的jQuery对象)

  jQuery.fn.end(函数用于返回最近一次"破坏性"操作之前的jQuery对象)



  jQuery.fn.find(选取每个匹配元素的符合指定表达式的后代元素,并以jQuery对象的形式返回)

  jQuery.fn.has(筛选出包含特定后代的元素,并以jQuery对象的形式返回)

  jQuery.fn.is(判断当前jQuery对象所匹配的元素是否符合指定的表达式。只要其中有至少一个元素符合该表达式就返回true,否则返回false)

  jQuery.fn.hasClass(指示当前jQuery对象所匹配的元素是否含有指定的css类名(elem.className),只需要其中有一个元素有即返回true)

  jQuery.fn.closest(从当前匹配元素开始,逐级向上级选取符合指定表达式的第一个元素,并以jQuery对象的形式返回)。

  jQuery.fn.filter(函数用于筛选出符合指定表达式的元素,并以jQuery对象的形式返回)

  jQuery.fn.has(函数用于筛选出包含特定后代的元素,并以jQuery对象的形式返回)

  jQuery.fn.not(函数用于从匹配元素中删除符合指定表达式的元素,并以jQuery对象的形式返回保留的元素)

  jQuery.fn.add(函数用于向当前匹配元素中添加符合指定表达式的元素,并以jQuery对象的形式返回,与not相反)

  jQuery.fn.addBack(函数用于将之前匹配的元素加入到当前匹配的元素中,并以新的jQuery对象的形式返回)

  jQuery.fn.children(函数用于选取每个匹配元素的子元素,并以jQuery对象的形式返回。你还可以使用选择器进一步缩小筛选范围,筛选出符合指定选择器的元素)

  jQuery.fn.parent(选取每个匹配元素的父元素,并以jQuery对象的形式返回)

  jQuery.fn.parents(选取每个匹配元素的祖先元素,并以jQuery对象的形式返回)

  jQuery.fn.parentsUntil(选取每个匹配元素的祖先元,直到遇到符合指定表达式的元素为止,并以jQuery对象的形式返回)

  jQuery.fn.next(筛选每个匹配元素之后紧邻的同辈元素,并以jQuery对象的形式返回)

  jQuery.fn.prev(筛选每个匹配元素之前紧邻的同辈元素,并以jQuery对象的形式返回)

  jQuery.fn.nextAll(选取每个匹配元素之后的所有同辈元素,并以jQuery对象的形式返回)

  jQuery.fn.prevAll(选取每个匹配元素之前的所有同辈元素,并以jQuery对象的形式返回)

  jQuery.fn.nextUntil(选取每个匹配元素之后所有的同辈元素,直到遇到符合指定表达式的元素为止,并以jQuery对象的形式返回)

  jQuery.fn.prevUntil(选取每个匹配元素之前所有的同辈元素,直到遇到符合指定表达式的元素为止,并以jQuery对象的形式返回)

  jQuery.fn.siblings(选取每个匹配元素的所有同辈元素(不包括自己),并以jQuery对象的形式返回)

  jQuery.fn.contents(函数用于选取当前匹配元素的所有子节点(包括文本节点、注释节点等),并以jQuery对象的形式返回)

  jQuery.fn.offsetParent(函数用于查找离当前匹配元素最近的被定位的祖辈元素,所谓"被定位的元素",就是元素的CSS position属性值为absolute、relative或fixed(只要不是默认的static即可))
*/

// Give the init function the jQuery prototype for later instantiation
jQuery.fn.init.prototype = jQuery.fn;
//这说明jQuery上和jQuery.fn下都有这么一个extend方法
jQuery.extend = jQuery.fn.extend = function() {
    //定义一些变量
    var options, name, src, copy, copyIsArray, clone,
        target = arguments[0] || {},//// 常见用法 jQuery.extend( obj1, obj2 ),此时,target为arguments[0]
        i = 1,
        length = arguments.length,
        deep = false;

    // Handle a deep copy situation //// 如果第一个参数为true,即 jQuery.extend( true, obj1, obj2 ); 的情况
    if ( typeof target === "boolean" ) {//看看是不是深拷贝的情况,类似于$.extend(true,a,b);第一个参数为boolean值true了,所以就属于深拷贝的情况 // 此时target是true
        deep = target;
        target = arguments[1] || {}; // target改为 obj1
        // skip the boolean and the target
        i = 2;
    }

    // Handle case when target is a string or something (possible in deep copy) // 处理奇怪的情况,比如 jQuery.extend( 'hello' , {nick: 'casper})~~
    if ( typeof target !== "object" && !jQuery.isFunction(target) ) {//看参数正确不
        target = {};
    }

    // extend jQuery itself if only one argument is passed
    if ( length === i ) {//看是否是插件(也就是jQuery.extend()还是jQuery.fn.extend())// 处理这种情况 jQuery.extend(obj),或 jQuery.fn.extend( obj )
        target = this; // jQuery.extend时,this指的是jQuery;jQuery.fn.extend时,this指的是jQuery.fn
        --i;
    }

    for ( ; i < length; i++ ) {//可能有多个对象的情况(vara{};$.extend(a,{name:'hello'},{age:30}))
        // Only deal with non-null/undefined values
        //是看你有多个对象,但对象到底有没有值呢
        if ( (options = arguments[ i ]) != null ) { // 比如 jQuery.extend( obj1, obj2, obj3, ojb4 ),options则为 obj2、obj3...
            // Extend the base object
            for ( name in options ) {
                src = target[ name ];
                copy = options[ name ];

                // Prevent never-ending loop
                if ( target === copy ) {//防止循环引用 // 防止自引用,不赘述
                    continue;
                }

                // Recurse(递归) if we're merging plain(普通的) objects or array//copy就是判断是否有第二个参数真正的去实现赋值操作
                //isPlainObject判断是否为对象自变量
                // 如果是深拷贝,且被拷贝的属性值本身是个对象
                if ( deep && copy && ( jQuery.isPlainObject(copy) || (copyIsArray = jQuery.isArray(copy)) ) ) {//深拷贝
                    if ( copyIsArray ) {//针对数组操作 // 被拷贝的属性值是个数组
                        copyIsArray = false;
                        clone = src && jQuery.isArray(src) ? src : [];

                    } else {//针对JSON操作 被拷贝的属性值是个plainObject,比如{ nick: 'casper' }
                        clone = src && jQuery.isPlainObject(src) ? src : {};
                    }

                    // Never move original objects, clone them
                    target[ name ] = jQuery.extend( deep, clone, copy );

                // Don't bring in undefined values
                } else if ( copy !== undefined ) {//浅拷贝 // 浅拷贝,且属性值不为undefined
                    target[ name ] = copy;
                }
            }
        }
    }

    // Return the modified object
    return target;
};
//扩展插件
jQuery.extend({
    // Unique for each copy of jQuery on the page//生成唯一JQ字符串(仅内部使用),replace( /\D/g, "" )是把非数字的替换为空,具备唯一性,对于做映射关系有帮助,例如数据缓存、事件操作、ajax操作都有用到它
    expando: "jQuery" + ( core_version + Math.random() ).replace( /\D/g, "" ),

    noConflict: function( deep ) {//防止冲突,deep传参时走的下面的分支是不一样的哟
        //jQuery是实例对象
        if ( window.$ === jQuery ) {
            window.$ = _$;
        }

        if ( deep && window.jQuery === jQuery ) {
            window.jQuery = _jQuery;
        }

        return jQuery;
    },

    // Is the DOM ready to be used? Set to true once it occurs.
    isReady: false,//Dom是否加载完(内部)

    // A counter to track how many items to wait for before
    // the ready event fires. See #6781
    readyWait: 1,//等待多少文件的计数器(内部)

    // Hold (or release) the ready event
    holdReady: function( hold ) {//推迟Dom触发
        if ( hold ) {
            jQuery.readyWait++;
        } else {
            //这就表示要释放一次
            jQuery.ready( true );
        }
    },

    // Handle when the DOM is ready
    ready: function( wait ) {//准备Dom触发

        // Abort if there are pending holds or we're already ready
        if ( wait === true ? --jQuery.readyWait : jQuery.isReady ) {
            return;
        }

        // Remember that the DOM is ready
        jQuery.isReady = true;

        // If a normal DOM Ready event fired, decrement, and wait if need be
        if ( wait !== true && --jQuery.readyWait > 0 ) {
            return;
        }

        // If there are functions bound, to execute//当走到这句话的时候,则说明Dom已经加载完毕了,则这样就可以执行fn了
        //document是指向fn的,也就是指向当加载完成后需要触发的动作fn,resolveWith()与resolve不同的是前者表示带参数,[jQuery]就是参数
        readyList.resolveWith( document, [ jQuery ] );

        // Trigger any bound ready events
        if ( jQuery.fn.trigger ) {//对于$(document).on('ready',function(){});首先判断是否有主动触发的事件,如果有则进行触发,例如$(document).on('ready',function(){alert(123);});
            jQuery( document ).trigger("ready").off("ready");
        }
    },

    // See test/unit/core.js for details concerning isFunction.
    // Since version 1.3, DOM methods and functions like alert
    // aren't supported. They return false on IE (#2968).
    isFunction: function( obj ) {//是否为函数(并没有真正意义上的判断是否为函数,以前的版本是做了判断,但是现在又改回来了)
        return jQuery.type(obj) === "function";
    },

    isArray: Array.isArray,//是否为数组

    isWindow: function( obj ) {//是否为window
        return obj != null && obj === obj.window;
    },

    isNumeric: function( obj ) {//是否为数字
        //如果obj能进行转换的话那就不是NAN,如果不能转换的话那就是NAN了。
        return !isNaN( parseFloat(obj) ) && isFinite( obj );
    },

    type: function( obj ) {//判断数据类型
        if ( obj == null ) {
            //这样String()类型转换是希望结果以字符串形式显示出来,如"null"
            return String( obj );
        }
        // Support: Safari <= 5.1 (functionish RegExp)
        return typeof obj === "object" || typeof obj === "function" ?
            class2type[ core_toString.call(obj) ] || "object" :
            typeof obj;
    },

    isPlainObject: function( obj ) {//是否为对象自变量(对象自变量就是JSON或者new Object()的形式)
        //例如,var obj={name:'hello'};var obj=new Object();所以就判断是否满足这2个形式就OK
        // Not plain objects:
        // - Any object or value whose internal [[Class]] property is not "[object Object]"
        // - DOM nodes
        // - window jQuery.isWindow( obj )是把window对象过滤掉

        if ( jQuery.type( obj ) !== "object" || obj.nodeType || jQuery.isWindow( obj ) ) {
            return false;
        }

        // Support: Firefox <20(因为老是调用的时候回出现递归泄露,所以try catch)
        // The try/catch suppresses exceptions thrown when attempting to access
        // the "constructor" property of certain host objects, ie. |window.location|
        // https://bugzilla.mozilla.org/show_bug.cgi?id=814622
        try {
            if ( obj.constructor &&
                    !core_hasOwn.call( obj.constructor.prototype, "isPrototypeOf" ) ) {
                return false;
            }
        } catch ( e ) {
            return false;
        }

        // If the function hasn't returned already, we're confident that
        // |obj| is a plain object, created by {} or constructed with new Object
        return true;
    },

    isEmptyObject: function( obj ) {//是否为空的对象
        var name;
        for ( name in obj ) {
            return false;
        }
        return true;
    },

    error: function( msg ) {//抛出异常
        throw new Error( msg );
    },

    // data: string of html
    // context (optional): If specified, the fragment will be created in this context, defaults to document
    // keepScripts (optional): If true, will include scripts passed in the html string
    parseHTML: function( data, context, keepScripts ) {//解析节点,把字符串转换成Dom节点集合
        //var str='<li></li><li></li>'
        //$.parseHTML(str);则节点被创造好,存放在了数组里[li,li]
        /*
        var str='<li></li><li></li><script></script>'
        console.log($.parseHTML(str,document,true));//则script是写到数组里的
        console.log($.parseHTML(str,document,false));//则script是不能写到数组里的
        */
        //如果不是字符串,那也就没有必要往下进行了
        if ( !data || typeof data !== "string" ) {
            return null;
        }
        if ( typeof context === "boolean" ) {
            keepScripts = context;
            context = false;
        }
        context = context || document;

        var parsed = rsingleTag.exec( data ),
            scripts = !keepScripts && [];

        // Single tag(对于单标签)例如<li></li>
        if ( parsed ) {
            return [ context.createElement( parsed[1] ) ];
        }

    //buildFragment 是一个私有函数,用来构建一个包含子节点 fragment 对象。buildFragment是一个内部的方法
    //对于多标签进行处理(例如,<li></li><li></li>),buildFragment是利用文档碎片对多标签进行处理的,创建Dom
        parsed = jQuery.buildFragment( [ data ], context, scripts );

        if ( scripts ) {
            jQuery( scripts ).remove();
        }

        return jQuery.merge( [], parsed.childNodes );
    },
  //将格式完好的JSON字符串转为与之对应的JavaScript对象,所谓"格式完好",就是要求指定的字符串必须符合严格的JSON格式,例如:属性名称必须加双引号、字符串值也必须用双引号。如果传入一个格式不"完好"的JSON字符串将抛出一个JS异常。
    parseJSON: JSON.parse,//解析JSON(将json形式的字符串转换为JSON,but IE6 and IE7不支持)
    //p.s  Json.parse只能解析严格模式的json字符串,而json.eval是能解析任意类型的字符串,json.stringify是将json转换成字符串

    // Cross-browser xml parsing 将字符串解析为对应的XML文档
    parseXML: function( data ) {解析XML
        var xml, tmp;
        //不是字符串的处理情况
        if ( !data || typeof data !== "string" ) {
            return null;
        }

        // Support: IE9
        try {
            //创建解析xml的实例对象(IE8以下不支持),IE8以下的使用的是ActiveXobject
            //DOMParser 对象解析 XML 文本并返回一个 XML Document 对象。要使用 DOMParser,使用不带参数的构造函数来实例化它,然后调用其 parseFromString() 方法:
            tmp = new DOMParser();
            //返回的就是文档的document对象,如果传入的数据出错,那就会跳到catch中的xml=undefined进行处理(这是指ie9数据出错时下一句会报错,而火狐是动态的创建parsererror,在下面报错)
            xml = tmp.parseFromString( data , "text/xml" );
        } catch ( e ) {
            xml = undefined;
        }
//这个是在火狐浏览器数据出错时执行的
        if ( !xml || xml.getElementsByTagName( "parsererror" ).length ) {
            jQuery.error( "Invalid XML: " + data );
        }
        return xml;
    },

    noop: function() {},//空函数

    // Evaluates a script in a global context
    globalEval: function( code ) {//全局解析JS,即是让在内部函数内部定义的变量变成全局的,从而在函数外面也可以被找到
        //例如,function test(){jQuery.globalEval("var newVar=true;")}  test();alert(newVar); newVar是可以被识别出来的
        var script,
                indirect = eval;

        code = jQuery.trim( code );

        if ( code ) {
            // If the code includes a valid, prologue position
            // strict mode pragma, execute code by injecting a
            // script tag into the document.
            if ( code.indexOf("use strict") === 1 ) {
                //如果是严格模式,则无法用eval解析,所以需用下面的处理方式,即创建script标签。
                script = document.createElement("script");
                script.text = code;
                document.head.appendChild( script ).parentNode.removeChild( script );
            } else {
            // Otherwise, avoid the DOM node creation, insertion
            // and removal by using an indirect global eval
            //如果不是严格模式,则就可以用eval进行解析咯
            //p.s.  eval既是windows下的一个属性又是js中的一个关键字,当你直接调用时,它会当做一个关键字使用,所以
            //只在局部作用域内有效,而windows.eval()就变成属性,则它内部的参数也会处理成windows下的,所以是可以全局解析到的
                indirect( code );
            }
        }
    },

    // Convert dashed to camelCase; used by the css and data modules
    // Microsoft forgot to hump their vendor prefix (#9572)
    camelCase: function( string ) {//转驼峰(内部方法),因为js中不能接受-字符
        return string.replace( rmsPrefix, "ms-" ).replace( rdashAlpha, fcamelCase );
    },

    nodeName: function( elem, name ) {//是否为指定节点名(内部方法)
        //为了能够全兼容,所以要转换成小写的,因为elem.nodeName测试时返回来的额是大写的
        //例如,alert($.nodeName(document.body,'html'))
        return elem.nodeName && elem.nodeName.toLowerCase() === name.toLowerCase();
    },

    // args is for internal usage only
    each: function( obj, callback, args ) {//遍历集合//args是用于jquery内部使用的
        //for循环是针对原声js的,而each是针对jqury对象的(数组、类数组、json集合)
        var value,
            i = 0,
            length = obj.length,
            //isArray就是判断是obj是类数组还是真正的数组,当然它不光针对他们,还针对jQuery对象this->{0:1,:,2:,length:3}所以是返回真的,所以这要和数组和json区分开来处理
            //如果返回真,则是数组操作或者jquery 对象this={...},否则是json的操作
            //jquery对象和json还是有些不同的,jquery对象的下标是0,1.。。的情况
            isArray = isArraylike( obj );

        if ( args ) {
            if ( isArray ) {
                for ( ; i < length; i++ ) {
                    value = callback.apply( obj[ i ], args );

                    if ( value === false ) {
                        break;
                    }
                }
            } else {
                for ( i in obj ) {
                    value = callback.apply( obj[ i ], args );

                    if ( value === false ) {
                        break;
                    }
                }
            }

        // A special, fast, case for the most common use of each
        } else {
            //如果是数组,则就用for循环,如果是json,则应用for in形式
            if ( isArray ) {
                for ( ; i < length; i++ ) {
                    value = callback.call( obj[ i ], i, obj[ i ] );

                    if ( value === false ) {
                        break;
                    }
                }
            } else {
                //json形式
                for ( i in obj ) {
                    value = callback.call( obj[ i ], i, obj[ i ] );

                    if ( value === false ) {
                        break;
                    }
                }
            }
        }

        return obj;
    },

    trim: function( text ) {//去前后空格(对原生trim进行二次封装)
        return text == null ? "" : core_trim.call( text );
    },

    // results is for internal usage only
    makeArray: function( arr, results ) {//类数组转真数组 其实它也可以将数字、字符串、json转换成数组的
        //例如,var str=1;console.log($.makeArray(str));
        如果makeArray有第二个参数,那么它就会用于内部使用,转换成json了,例如,上面例子调用改成console.log($.makeArray(str,{length:0})),注意是一定要有length属性的,这样才能转换成相应的json
        var ret = results || [];

        if ( arr != null ) {
            if ( isArraylike( Object(arr) ) ) {
                //Object(123) Number {[[PrimitiveValue]]: 123} 所以对于123即使object也会返回false的
                jQuery.merge( ret,
                    typeof arr === "string" ?
                    [ arr ] : arr
                );
            } else {
                core_push.call( ret, arr );
            }
        }

        return ret;
    },

    inArray: function( elem, arr, i ) {//数组版indexOf
        return arr == null ? -1 : core_indexOf.call( arr, elem, i );
    },

    merge: function( first, second ) {//合并数组
        var l = second.length,
            i = first.length,
            j = 0;

        if ( typeof l === "number" ) {//$.merge(['a','b'],['c','d']);
            for ( ; j < l; j++ ) {
                first[ i++ ] = second[ j ];
            }
        } else {//$.merge(['a','b'],{0:'c',1:'d'}),是可以没有长度的 
            while ( second[j] !== undefined ) {
                first[ i++ ] = second[ j++ ];
            }
        }

        first.length = i;

        return first;
    },

    grep: function( elems, callback, inv ) {//过滤新数组 函数目的是过滤出用户指定的数据。一般来说第三个参数不传或传为false,callback是一个过滤器,过滤成功返回true,过滤失败返回false。最终grep函数将callback返回成功的素有elem元素返回。这个函数无论是在jQuery内部,或者我们自己使用都很有作用
        /*
        var arr=[1,2,3,4];
        arr=$.grep(arr,function(n,i){
        return n>2;
        });
        则返回n>2的数组元素
        如果传入了第三个参数true
        arr=$.grep(arr,function(n,i){
        return n>2;
        },true);
        则会返回n<=2的情况
        */
        var retVal,
            ret = [],
            i = 0,
            length = elems.length;
        inv = !!inv;

        // Go through the array, only saving the items
        // that pass the validator function
        for ( ; i < length; i++ ) {
            retVal = !!callback( elems[ i ], i );
            if ( inv !== retVal ) {
                ret.push( elems[ i ] );
            }
        }

        return ret;
    },

    // arg is for internal usage only
    map: function( elems, callback, arg ) {//映射新数组
        /*
        var arr=[1,2,3,4];
        arr=$.map(arr,function(n){
        return n+1;
        })
        则这样就会映射成新的数组
        */
        var value,
            i = 0,
            length = elems.length,
            isArray = isArraylike( elems ),
            ret = [];

        // Go through the array, translating each of the items to their
        if ( isArray ) {
            for ( ; i < length; i++ ) {
                value = callback( elems[ i ], i, arg );

                if ( value != null ) {
                    ret[ ret.length ] = value;
                }
            }

        // Go through every key on the object,
        } else {
            for ( i in elems ) {
                value = callback( elems[ i ], i, arg );

                if ( value != null ) {
                    ret[ ret.length ] = value;
                }
            }
        }

        // Flatten any nested arrays避免出现复合数组所做的操作apply([],ret),把ret给[]
        return core_concat.apply( [], ret );
    },

    // A global GUID counter for objects
    guid: 1,//唯一标识符(内部),比如和事件操作都是有关系的。

    // Bind a function to a context, optionally partially applying any
    // arguments.
    proxy: function( fn, context ) {//改了this指向
        var tmp, args, proxy;

    //处理简化写法$(document).click($.proxy(obj,'show'));
        if ( typeof context === "string" ) {
            tmp = fn[ context ];
            context = fn;
            fn = tmp;
        }

        // Quick check to determine if target is callable, in the spec
        // this throws a TypeError, but we will just return undefined.
        if ( !jQuery.isFunction( fn ) ) {
            return undefined;
        }

        // Simulated bind
        args = core_slice.call( arguments, 2 );
        proxy = function() {
            return fn.apply( context || this, args.concat( core_slice.call( arguments ) ) );
        };

        // Set the guid of unique handler to the same of original handler, so it can be removed
        //设置唯一的标识
        proxy.guid = fn.guid = fn.guid || jQuery.guid++;

        return proxy;
    },

    // Multifunctional method to get and set values of a collection
    // The value/s can optionally be executed if it's a function
    access: function( elems, fn, key, value, chainable, emptyGet, raw ) {//多功能值操作(内部)fn是回调函数 chainable若为true,则我们是要设置,否则,我们是要获取
        var i = 0,
            length = elems.length,
            bulk = key == null;

        // Sets many values
        if ( jQuery.type( key ) === "object" ) {
            chainable = true;
            for ( i in key ) {
                jQuery.access( elems, fn, i, key[i], true, emptyGet, raw );
            }

        // Sets one value
        } else if ( value !== undefined ) {
            chainable = true;

            if ( !jQuery.isFunction( value ) ) {
                raw = true;
            }

            if ( bulk ) {
                // Bulk operations run against the entire set
                if ( raw ) {
                    fn.call( elems, value );
                    fn = null;

                // ...except when executing function values
                } else {
                    bulk = fn;
                    fn = function( elem, key, value ) {
                        return bulk.call( jQuery( elem ), value );
                    };
                }
            }

            if ( fn ) {
                for ( ; i < length; i++ ) {
                    fn( elems[i], key, raw ? value : value.call( elems[i], i, fn( elems[i], key ) ) );
                }
            }
        }

        return chainable ?
            elems :

            // Gets 获取的操作在这里哟
            bulk ?
                fn.call( elems ) :
                length ? fn( elems[0], key ) : emptyGet;
    },

    now: Date.now,//当前时间

    // A method for quickly swapping in/out CSS properties to get correct calculations.
    // Note: this method belongs to the css module but it's needed here for the support module.
    // If support gets modularized, this method should be moved back to the css module.
    swap: function( elem, options, callback, args ) {CSS交换(内部)例如获取隐藏元素的宽度,jquery就可以获得,而原生js不能获得是因为jquery的swap操作“偷梁换柱”的结果
        var ret, name,
            old = {};

        // Remember the old values, and insert the new ones
        for ( name in options ) {
            old[ name ] = elem.style[ name ];
            elem.style[ name ] = options[ name ];
        }

        ret = callback.apply( elem, args || [] );

        // Revert the old values
        for ( name in options ) {
            elem.style[ name ] = old[ name ];
        }

        return ret;
    }
});

jQuery.ready.promise = function( obj ) {//创建了延迟对象,promise在外面是不能被修改的
    if ( !readyList ) {
    //创建延迟对象
        readyList = jQuery.Deferred();

        // Catch cases where $(document).ready() is called after the browser event has already occurred.
        // we once tried to use readyState "interactive" here, but it caused issues like the one
        // discovered by ChrisS here: http://bugs.jquery.com/ticket/12282#comment:15
        if ( document.readyState === "complete" ) {
            // Handle it asynchronously to allow scripts the opportunity to delay ready
            //保证让其延后触发,因为IE版本在可能差一点点就完成的时候它就触发了,所以IE有点帮倒忙了,所以保证IE下也是OK的。
            setTimeout( jQuery.ready );

        } else {

            // Use the handy event callback//complted是回调函数,它可以在jQuery源码中找寻到
            //浏览器中可能会对load进行缓存,所以加载的比较快些,所以写了下面2个语句,DOMContentLoaded和load无论哪个先触发好我们都执行相同的回调
            //函数completed.
            document.addEventListener( "DOMContentLoaded", completed, false );

            // A fallback to window.onload, that will always work
            window.addEventListener( "load", completed, false );
        }
    }
    //promise是保证状态在外面是不会修改的
    return readyList.promise( obj );
};

// Populate the class2type map
jQuery.each("Boolean Number String Function Array Date RegExp Object Error".split(" "), function(i, name) {
    /*
    对于alert($.type([]));按理应该弹出[Object Array],但这样太长了,所以下面就是对其一种转换,最终弹出的是array.
    */
    class2type[ "[object " + name + "]" ] = name.toLowerCase();
});

//简单的说:类数组对象是有一个数值length属性和对应非负整数属性的对象。源码就是判断一个对象是否为类数组对象。
//测试总结:三种情况下返回true。第一种:length恒等于0;第二种:本身就是Array类型;第三种:length>0,同时length是number类型,同时(length-1) in obj为true!
function isArraylike( obj ) {
    var length = obj.length,
        type = jQuery.type( obj );
//为什么要对window单独做判断呢,是因为害怕执行下面的操作的时候window下也挂载了length属性
//如果是函数,或者window那么直接返回false
    if ( jQuery.isWindow( obj ) ) {
        return false;
    }

    if ( obj.nodeType === 1 && length ) {
        return true;
    }

  //length是数字类型,同时length>0而且length-1要存在
    return type === "array" || type !== "function" &&
        ( length === 0 ||
        typeof length === "number" && length > 0 && ( length - 1 ) in obj );
}

// All jQuery objects should point back to these 获取jQuery document根节点
jQuery定义了rootjQuery,同时赋予了它合理的上下文,即document,这样有助于压缩
rootjQuery = jQuery(document);
/*!
 * Sizzle CSS Selector Engine v1.9.4-pre
 * http://sizzlejs.com/
 *
 * Copyright 2013 jQuery Foundation, Inc. and other contributors
 * Released under the MIT license
 * http://jquery.org/license
 *
 * Date: 2013-06-03
 */
(function( window, undefined ) {

var i,
    support,
    cachedruns,
    Expr,
    getText,
    isXML,
    compile,
    outermostContext,
    sortInput,

    // Local document vars
    setDocument,
    document,
    docElem,
    documentIsHTML,
    rbuggyQSA,
    rbuggyMatches,
    matches,
    contains,

    // Instance-specific data
    expando = "sizzle" + -(new Date()),
    preferredDoc = window.document,
    dirruns = 0,
    done = 0,
    classCache = createCache(),
    //jQuery在词法解析函数tokenize开始解析之前用到了一个比较巧妙的地方,Sizzle把每次查询结果缓存了起来,如果下一次有相同的查询,则直接使用缓存中的查询结果,而不需要重新查询。
    tokenCache = createCache(),
    compilerCache = createCache(),
    hasDuplicate = false,
    sortOrder = function( a, b ) {
        if ( a === b ) {
            hasDuplicate = true;
            return 0;
        }
        return 0;
    },

    // General-purpose constants
    strundefined = typeof undefined,
    MAX_NEGATIVE = 1 << 31,

    // Instance methods
    hasOwn = ({}).hasOwnProperty,
    arr = [],
    pop = arr.pop,
    push_native = arr.push,
    push = arr.push,
    slice = arr.slice,
    // Use a stripped-down indexOf if we can't use a native one
    indexOf = arr.indexOf || function( elem ) {
        var i = 0,
            len = this.length;
        for ( ; i < len; i++ ) {
            if ( this[i] === elem ) {
                return i;
            }
        }
        return -1;
    },

    booleans = "checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped",

    // Regular expressions

    // Whitespace characters http://www.w3.org/TR/css3-selectors/#whitespace
    whitespace = "[\\x20\\t\\r\\n\\f]",
    // http://www.w3.org/TR/css3-syntax/#characters
    characterEncoding = "(?:\\\\.|[\\w-]|[^\\x00-\\xa0])+",

    // Loosely modeled on CSS identifier characters
    // An unquoted value should be a CSS identifier http://www.w3.org/TR/css3-selectors/#attribute-selectors
    // Proper syntax: http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
    identifier = characterEncoding.replace( "w", "w#" ),

    // Acceptable operators http://www.w3.org/TR/selectors/#attribute-selectors
    attributes = "\\[" + whitespace + "*(" + characterEncoding + ")" + whitespace +
        "*(?:([*^$|!~]?=)" + whitespace + "*(?:(['\"])((?:\\\\.|[^\\\\])*?)\\3|(" + identifier + ")|)|)" + whitespace + "*\\]",

    // Prefer arguments quoted,
    //   then not containing pseudos/brackets,
    //   then attribute selectors/non-parenthetical expressions,
    //   then anything else
    // These preferences are here to reduce the number of selectors
    //   needing tokenize in the PSEUDO preFilter
    pseudos = ":(" + characterEncoding + ")(?:\\(((['\"])((?:\\\\.|[^\\\\])*?)\\3|((?:\\\\.|[^\\\\()[\\]]|" + attributes.replace( 3, 8 ) + ")*)|.*)\\)|)",

    // Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
    rtrim = new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" ),

    rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
    rcombinators = new RegExp( "^" + whitespace + "*([>+~]|" + whitespace + ")" + whitespace + "*" ),

    rsibling = new RegExp( whitespace + "*[+~]" ),
    rattributeQuotes = new RegExp( "=" + whitespace + "*([^\\]'\"]*)" + whitespace + "*\\]", "g" ),

    rpseudo = new RegExp( pseudos ),
    ridentifier = new RegExp( "^" + identifier + "$" ),

    matchExpr = {
        "ID": new RegExp( "^#(" + characterEncoding + ")" ),
        "CLASS": new RegExp( "^\\.(" + characterEncoding + ")" ),
        "TAG": new RegExp( "^(" + characterEncoding.replace( "w", "w*" ) + ")" ),
        "ATTR": new RegExp( "^" + attributes ),
        "PSEUDO": new RegExp( "^" + pseudos ),
        "CHILD": new RegExp( "^:(only|first|last|nth|nth-last)-(child|of-type)(?:\\(" + whitespace +
            "*(even|odd|(([+-]|)(\\d*)n|)" + whitespace + "*(?:([+-]|)" + whitespace +
            "*(\\d+)|))" + whitespace + "*\\)|)", "i" ),
        "bool": new RegExp( "^(?:" + booleans + ")$", "i" ),
        // For use in libraries implementing .is()
        // We use this for POS matching in `select`
        "needsContext": new RegExp( "^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" +
            whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
    },

    rnative = /^[^{]+\{\s*\[native \w/,

    // Easily-parseable/retrievable ID or TAG or CLASS selectors
    rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,

    rinputs = /^(?:input|select|textarea|button)$/i,
    rheader = /^h\d$/i,

    rescape = /'|\\/g,

    // CSS escapes http://www.w3.org/TR/CSS21/syndata.html#escaped-characters
    runescape = new RegExp( "\\\\([\\da-f]{1,6}" + whitespace + "?|(" + whitespace + ")|.)", "ig" ),
    funescape = function( _, escaped, escapedWhitespace ) {
        var high = "0x" + escaped - 0x10000;
        // NaN means non-codepoint
        // Support: Firefox
        // Workaround erroneous numeric interpretation of +"0x"
        return high !== high || escapedWhitespace ?
            escaped :
            // BMP codepoint
            high < 0 ?
                String.fromCharCode( high + 0x10000 ) :
                // Supplemental Plane codepoint (surrogate pair)
                String.fromCharCode( high >> 10 | 0xD800, high & 0x3FF | 0xDC00 );
    };

// Optimize for push.apply( _, NodeList )
try {
    push.apply(
        (arr = slice.call( preferredDoc.childNodes )),
        preferredDoc.childNodes
    );
    // Support: Android<4.0
    // Detect silently failing push.apply
    arr[ preferredDoc.childNodes.length ].nodeType;
} catch ( e ) {
    push = { apply: arr.length ?

        // Leverage slice if possible
        function( target, els ) {
            push_native.apply( target, slice.call(els) );
        } :

        // Support: IE<9
        // Otherwise append directly
        function( target, els ) {
            var j = target.length,
                i = 0;
            // Can't trust NodeList.length
            while ( (target[j++] = els[i++]) ) {}
            target.length = j - 1;
        }
    };
}

function Sizzle( selector, context, results, seed ) {
    var match, elem, m, nodeType,
        // QSA vars
        i, groups, old, nid, newContext, newSelector;

    if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
        setDocument( context );
    }

    context = context || document;
    results = results || [];

    if ( !selector || typeof selector !== "string" ) {
        return results;
    }

    if ( (nodeType = context.nodeType) !== 1 && nodeType !== 9 ) {
        return [];
    }

    if ( documentIsHTML && !seed ) {

        // Shortcuts
        if ( (match = rquickExpr.exec( selector )) ) {
            // Speed-up: Sizzle("#ID")
            if ( (m = match[1]) ) {
                if ( nodeType === 9 ) {
                    elem = context.getElementById( m );
                    // Check parentNode to catch when Blackberry 4.6 returns
                    // nodes that are no longer in the document #6963
                    if ( elem && elem.parentNode ) {
                        // Handle the case where IE, Opera, and Webkit return items
                        // by name instead of ID
                        if ( elem.id === m ) {
                            results.push( elem );
                            return results;
                        }
                    } else {
                        return results;
                    }
                } else {
                    // Context is not a document
                    if ( context.ownerDocument && (elem = context.ownerDocument.getElementById( m )) &&
                        contains( context, elem ) && elem.id === m ) {
                        results.push( elem );
                        return results;
                    }
                }

            // Speed-up: Sizzle("TAG")
            } else if ( match[2] ) {
                push.apply( results, context.getElementsByTagName( selector ) );
                return results;

            // Speed-up: Sizzle(".CLASS")
            } else if ( (m = match[3]) && support.getElementsByClassName && context.getElementsByClassName ) {
                push.apply( results, context.getElementsByClassName( m ) );
                return results;
            }
        }

        // QSA path
        if ( support.qsa && (!rbuggyQSA || !rbuggyQSA.test( selector )) ) {
            nid = old = expando;
            newContext = context;
            newSelector = nodeType === 9 && selector;

            // qSA works strangely on Element-rooted queries
            // We can work around this by specifying an extra ID on the root
            // and working up from there (Thanks to Andrew Dupont for the technique)
            // IE 8 doesn't work on object elements
            if ( nodeType === 1 && context.nodeName.toLowerCase() !== "object" ) {
                groups = tokenize( selector );

                if ( (old = context.getAttribute("id")) ) {
                    nid = old.replace( rescape, "\\$&" );
                } else {
                    context.setAttribute( "id", nid );
                }
                nid = "[id='" + nid + "'] ";

                i = groups.length;
                while ( i-- ) {
                    groups[i] = nid + toSelector( groups[i] );
                }
                newContext = rsibling.test( selector ) && context.parentNode || context;
                newSelector = groups.join(",");
            }

            if ( newSelector ) {
                try {
                    push.apply( results,
                        newContext.querySelectorAll( newSelector )
                    );
                    return results;
                } catch(qsaError) {
                } finally {
                    if ( !old ) {
                        context.removeAttribute("id");
                    }
                }
            }
        }
    }

    // All others
    return select( selector.replace( rtrim, "$1" ), context, results, seed );
}

/**
 * Create key-value caches of limited size
 * @returns {Function(string, Object)} Returns the Object data after storing it on itself with
 *    property name the (space-suffixed) string and (if the cache is larger than Expr.cacheLength)
 *    deleting the oldest entry
 */
function createCache() {
    var keys = [];

    function cache( key, value ) {
        // Use (key + " ") to avoid collision with native prototype properties (see Issue #157)
        if ( keys.push( key += " " ) > Expr.cacheLength ) {
            // Only keep the most recent entries
            delete cache[ keys.shift() ];
        }
        return (cache[ key ] = value);
    }
    return cache;
}

/**
 * Mark a function for special use by Sizzle
 * @param {Function} fn The function to mark
 */
function markFunction( fn ) {
    fn[ expando ] = true;
    return fn;
}

/**
 * Support testing using an element
 * @param {Function} fn Passed the created div and expects a boolean result
 */
function assert( fn ) {
    var div = document.createElement("div");

    try {
        return !!fn( div );
    } catch (e) {
        return false;
    } finally {
        // Remove from its parent by default
        if ( div.parentNode ) {
            div.parentNode.removeChild( div );
        }
        // release memory in IE
        div = null;
    }
}

/**
 * Adds the same handler for all of the specified attrs
 * @param {String} attrs Pipe-separated list of attributes
 * @param {Function} handler The method that will be applied
 */
function addHandle( attrs, handler ) {
    var arr = attrs.split("|"),
        i = attrs.length;

    while ( i-- ) {
        Expr.attrHandle[ arr[i] ] = handler;
    }
}

/**
 * Checks document order of two siblings
 * @param {Element} a
 * @param {Element} b
 * @returns {Number} Returns less than 0 if a precedes b, greater than 0 if a follows b
 */
function siblingCheck( a, b ) {
    var cur = b && a,
        diff = cur && a.nodeType === 1 && b.nodeType === 1 &&
            ( ~b.sourceIndex || MAX_NEGATIVE ) -
            ( ~a.sourceIndex || MAX_NEGATIVE );

    // Use IE sourceIndex if available on both nodes
    if ( diff ) {
        return diff;
    }

    // Check if b follows a
    if ( cur ) {
        while ( (cur = cur.nextSibling) ) {
            if ( cur === b ) {
                return -1;
            }
        }
    }

    return a ? 1 : -1;
}

/**
 * Returns a function to use in pseudos for input types
 * @param {String} type
 */
function createInputPseudo( type ) {
    return function( elem ) {
        var name = elem.nodeName.toLowerCase();
        return name === "input" && elem.type === type;
    };
}

/**
 * Returns a function to use in pseudos for buttons
 * @param {String} type
 */
function createButtonPseudo( type ) {
    return function( elem ) {
        var name = elem.nodeName.toLowerCase();
        return (name === "input" || name === "button") && elem.type === type;
    };
}

/**
 * Returns a function to use in pseudos for positionals
 * @param {Function} fn
 */
function createPositionalPseudo( fn ) {
    return markFunction(function( argument ) {
        argument = +argument;
        return markFunction(function( seed, matches ) {
            var j,
                matchIndexes = fn( [], seed.length, argument ),
                i = matchIndexes.length;

            // Match elements found at the specified indexes
            while ( i-- ) {
                if ( seed[ (j = matchIndexes[i]) ] ) {
                    seed[j] = !(matches[j] = seed[j]);
                }
            }
        });
    });
}

/**
 * Detect xml
 * @param {Element|Object} elem An element or a document
 */
isXML = Sizzle.isXML = function( elem ) {
    // documentElement is verified for cases where it doesn't yet exist
    // (such as loading iframes in IE - #4833)
    var documentElement = elem && (elem.ownerDocument || elem).documentElement;
    return documentElement ? documentElement.nodeName !== "HTML" : false;
};

// Expose support vars for convenience
support = Sizzle.support = {};

/**
 * Sets document-related variables once based on the current document
 * @param {Element|Object} [doc] An element or document object to use to set the document
 * @returns {Object} Returns the current document
 */
 //该函数功能是设置document,探测浏览器对各个方法属性的支持情况保存在support对象中,并且给Sizzle选择器的匹配关键变量添加匹配相关的hooks,初始化contains和sortOrder函数。
setDocument = Sizzle.setDocument = function( node ) {
    var doc = node ? node.ownerDocument || node : preferredDoc,
        parent = doc.defaultView;

    // If no document and documentElement is available, return
    if ( doc === document || doc.nodeType !== 9 || !doc.documentElement ) {
        return document;
    }

    // Set our document
    document = doc;
    docElem = doc.documentElement;

    // Support tests
    documentIsHTML = !isXML( doc );

    // Support: IE>8
    // If iframe document is assigned to "document" variable and if iframe has been reloaded,
    // IE will throw "permission denied" error when accessing "document" variable, see jQuery #13936
    // IE6-8 do not support the defaultView property so parent will be undefined
    if ( parent && parent.attachEvent && parent !== parent.top ) {
        parent.attachEvent( "onbeforeunload", function() {
            setDocument();
        });
    }

    /* Attributes
    ---------------------------------------------------------------------- */

    // Support: IE<8
    // Verify that getAttribute really returns attributes and not properties (excepting IE8 booleans)
    support.attributes = assert(function( div ) {
        div.className = "i";
        return !div.getAttribute("className");
    });

    /* getElement(s)By*
    ---------------------------------------------------------------------- */

    // Check if getElementsByTagName("*") returns only elements
    support.getElementsByTagName = assert(function( div ) {
        div.appendChild( doc.createComment("") );
        return !div.getElementsByTagName("*").length;
    });

    // Check if getElementsByClassName can be trusted
    support.getElementsByClassName = assert(function( div ) {
        div.innerHTML = "<div class='a'></div><div class='a i'></div>";

        // Support: Safari<4
        // Catch class over-caching
        div.firstChild.className = "i";
        // Support: Opera<10
        // Catch gEBCN failure to find non-leading classes
        return div.getElementsByClassName("i").length === 2;
    });

    // Support: IE<10
    // Check if getElementById returns elements by name
    // The broken getElementById methods don't pick up programatically-set names,
    // so use a roundabout getElementsByName test
    support.getById = assert(function( div ) {
        docElem.appendChild( div ).id = expando;
        return !doc.getElementsByName || !doc.getElementsByName( expando ).length;
    });

    // ID find and filter
    if ( support.getById ) {
        Expr.find["ID"] = function( id, context ) {
            if ( typeof context.getElementById !== strundefined && documentIsHTML ) {
                var m = context.getElementById( id );
                // Check parentNode to catch when Blackberry 4.6 returns
                // nodes that are no longer in the document #6963
                return m && m.parentNode ? [m] : [];
            }
        };
        Expr.filter["ID"] = function( id ) {
            var attrId = id.replace( runescape, funescape );
            return function( elem ) {
                return elem.getAttribute("id") === attrId;
            };
        };
    } else {
        // Support: IE6/7
        // getElementById is not reliable as a find shortcut
        delete Expr.find["ID"];

        Expr.filter["ID"] =  function( id ) {
            var attrId = id.replace( runescape, funescape );
            return function( elem ) {
                var node = typeof elem.getAttributeNode !== strundefined && elem.getAttributeNode("id");
                return node && node.value === attrId;
            };
        };
    }

    // Tag
    Expr.find["TAG"] = support.getElementsByTagName ?
        function( tag, context ) {
            if ( typeof context.getElementsByTagName !== strundefined ) {
                return context.getElementsByTagName( tag );
            }
        } :
        function( tag, context ) {
            var elem,
                tmp = [],
                i = 0,
                results = context.getElementsByTagName( tag );

            // Filter out possible comments
            if ( tag === "*" ) {
                while ( (elem = results[i++]) ) {
                    if ( elem.nodeType === 1 ) {
                        tmp.push( elem );
                    }
                }

                return tmp;
            }
            return results;
        };

    // Class
    Expr.find["CLASS"] = support.getElementsByClassName && function( className, context ) {
        if ( typeof context.getElementsByClassName !== strundefined && documentIsHTML ) {
            return context.getElementsByClassName( className );
        }
    };

    /* QSA/matchesSelector
    ---------------------------------------------------------------------- */

    // QSA and matchesSelector support

    // matchesSelector(:active) reports false when true (IE9/Opera 11.5)
    rbuggyMatches = [];

    // qSa(:focus) reports false when true (Chrome 21)
    // We allow this because of a bug in IE8/9 that throws an error
    // whenever `document.activeElement` is accessed on an iframe
    // So, we allow :focus to pass through QSA all the time to avoid the IE error
    // See http://bugs.jquery.com/ticket/13378
    rbuggyQSA = [];

    if ( (support.qsa = rnative.test( doc.querySelectorAll )) ) {
        // Build QSA regex
        // Regex strategy adopted from Diego Perini
        assert(function( div ) {
            // Select is set to empty string on purpose
            // This is to test IE's treatment of not explicitly
            // setting a boolean content attribute,
            // since its presence should be enough
            // http://bugs.jquery.com/ticket/12359
            div.innerHTML = "<select><option selected=''></option></select>";

            // Support: IE8
            // Boolean attributes and "value" are not treated correctly
            if ( !div.querySelectorAll("[selected]").length ) {
                rbuggyQSA.push( "\\[" + whitespace + "*(?:value|" + booleans + ")" );
            }

            // Webkit/Opera - :checked should return selected option elements
            // http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
            // IE8 throws error here and will not see later tests
            if ( !div.querySelectorAll(":checked").length ) {
                rbuggyQSA.push(":checked");
            }
        });

        assert(function( div ) {

            // Support: Opera 10-12/IE8
            // ^= $= *= and empty values
            // Should not select anything
            // Support: Windows 8 Native Apps
            // The type attribute is restricted during .innerHTML assignment
            var input = doc.createElement("input");
            input.setAttribute( "type", "hidden" );
            div.appendChild( input ).setAttribute( "t", "" );

            if ( div.querySelectorAll("[t^='']").length ) {
                rbuggyQSA.push( "[*^$]=" + whitespace + "*(?:''|\"\")" );
            }

            // FF 3.5 - :enabled/:disabled and hidden elements (hidden elements are still enabled)
            // IE8 throws error here and will not see later tests
            if ( !div.querySelectorAll(":enabled").length ) {
                rbuggyQSA.push( ":enabled", ":disabled" );
            }

            // Opera 10-11 does not throw on post-comma invalid pseudos
            div.querySelectorAll("*,:x");
            rbuggyQSA.push(",.*:");
        });
    }

    if ( (support.matchesSelector = rnative.test( (matches = docElem.webkitMatchesSelector ||
        docElem.mozMatchesSelector ||
        docElem.oMatchesSelector ||
        docElem.msMatchesSelector) )) ) {

        assert(function( div ) {
            // Check to see if it's possible to do matchesSelector
            // on a disconnected node (IE 9)
            support.disconnectedMatch = matches.call( div, "div" );

            // This should fail with an exception
            // Gecko does not error, returns false instead
            matches.call( div, "[s!='']:x" );
            rbuggyMatches.push( "!=", pseudos );
        });
    }

    rbuggyQSA = rbuggyQSA.length && new RegExp( rbuggyQSA.join("|") );
    rbuggyMatches = rbuggyMatches.length && new RegExp( rbuggyMatches.join("|") );

    /* Contains
    ---------------------------------------------------------------------- */

    // Element contains another
    // Purposefully does not implement inclusive descendent
    // As in, an element does not contain itself
    contains = rnative.test( docElem.contains ) || docElem.compareDocumentPosition ?
        function( a, b ) {
            var adown = a.nodeType === 9 ? a.documentElement : a,
                bup = b && b.parentNode;
            return a === bup || !!( bup && bup.nodeType === 1 && (
                adown.contains ?
                    adown.contains( bup ) :
                    a.compareDocumentPosition && a.compareDocumentPosition( bup ) & 16
            ));
        } :
        function( a, b ) {
            if ( b ) {
                while ( (b = b.parentNode) ) {
                    if ( b === a ) {
                        return true;
                    }
                }
            }
            return false;
        };

    /* Sorting
    ---------------------------------------------------------------------- */

    // Document order sorting
    sortOrder = docElem.compareDocumentPosition ?
    function( a, b ) {

        // Flag for duplicate removal
        if ( a === b ) {
            hasDuplicate = true;
            return 0;
        }

        var compare = b.compareDocumentPosition && a.compareDocumentPosition && a.compareDocumentPosition( b );

        if ( compare ) {
            // Disconnected nodes
            if ( compare & 1 ||
                (!support.sortDetached && b.compareDocumentPosition( a ) === compare) ) {

                // Choose the first element that is related to our preferred document
                if ( a === doc || contains(preferredDoc, a) ) {
                    return -1;
                }
                if ( b === doc || contains(preferredDoc, b) ) {
                    return 1;
                }

                // Maintain original order
                return sortInput ?
                    ( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
                    0;
            }

            return compare & 4 ? -1 : 1;
        }

        // Not directly comparable, sort on existence of method
        return a.compareDocumentPosition ? -1 : 1;
    } :
    function( a, b ) {
        var cur,
            i = 0,
            aup = a.parentNode,
            bup = b.parentNode,
            ap = [ a ],
            bp = [ b ];

        // Exit early if the nodes are identical
        if ( a === b ) {
            hasDuplicate = true;
            return 0;

        // Parentless nodes are either documents or disconnected
        } else if ( !aup || !bup ) {
            return a === doc ? -1 :
                b === doc ? 1 :
                aup ? -1 :
                bup ? 1 :
                sortInput ?
                ( indexOf.call( sortInput, a ) - indexOf.call( sortInput, b ) ) :
                0;

        // If the nodes are siblings, we can do a quick check
        } else if ( aup === bup ) {
            return siblingCheck( a, b );
        }

        // Otherwise we need full lists of their ancestors for comparison
        cur = a;
        while ( (cur = cur.parentNode) ) {
            ap.unshift( cur );
        }
        cur = b;
        while ( (cur = cur.parentNode) ) {
            bp.unshift( cur );
        }

        // Walk down the tree looking for a discrepancy
        while ( ap[i] === bp[i] ) {
            i++;
        }

        return i ?
            // Do a sibling check if the nodes have a common ancestor
            siblingCheck( ap[i], bp[i] ) :

            // Otherwise nodes in our document sort first
            ap[i] === preferredDoc ? -1 :
            bp[i] === preferredDoc ? 1 :
            0;
    };

    return doc;
};

Sizzle.matches = function( expr, elements ) {
    return Sizzle( expr, null, null, elements );
};

Sizzle.matchesSelector = function( elem, expr ) {
    // Set document vars if needed
    if ( ( elem.ownerDocument || elem ) !== document ) {
        setDocument( elem );
    }

    // Make sure that attribute selectors are quoted
    expr = expr.replace( rattributeQuotes, "='$1']" );

    if ( support.matchesSelector && documentIsHTML &&
        ( !rbuggyMatches || !rbuggyMatches.test( expr ) ) &&
        ( !rbuggyQSA     || !rbuggyQSA.test( expr ) ) ) {

        try {
            var ret = matches.call( elem, expr );

            // IE 9's matchesSelector returns false on disconnected nodes
            if ( ret || support.disconnectedMatch ||
                    // As well, disconnected nodes are said to be in a document
                    // fragment in IE 9
                    elem.document && elem.document.nodeType !== 11 ) {
                return ret;
            }
        } catch(e) {}
    }

    return Sizzle( expr, document, null, [elem] ).length > 0;
};

Sizzle.contains = function( context, elem ) {
    // Set document vars if needed
    if ( ( context.ownerDocument || context ) !== document ) {
        setDocument( context );
    }
    return contains( context, elem );
};

Sizzle.attr = function( elem, name ) {
    // Set document vars if needed
    if ( ( elem.ownerDocument || elem ) !== document ) {
        setDocument( elem );
    }

    var fn = Expr.attrHandle[ name.toLowerCase() ],
        // Don't get fooled by Object.prototype properties (jQuery #13807)
        val = fn && hasOwn.call( Expr.attrHandle, name.toLowerCase() ) ?
            fn( elem, name, !documentIsHTML ) :
            undefined;

    return val === undefined ?
        support.attributes || !documentIsHTML ?
            elem.getAttribute( name ) :
            (val = elem.getAttributeNode(name)) && val.specified ?
                val.value :
                null :
        val;
};

Sizzle.error = function( msg ) {
    throw new Error( "Syntax error, unrecognized expression: " + msg );
};

/**
 * Document sorting and removing duplicates
 * @param {ArrayLike} results
 */
Sizzle.uniqueSort = function( results ) {
    var elem,
        duplicates = [],
        j = 0,
        i = 0;

    // Unless we *know* we can detect duplicates, assume their presence
    hasDuplicate = !support.detectDuplicates;
    sortInput = !support.sortStable && results.slice( 0 );
    results.sort( sortOrder );

    if ( hasDuplicate ) {
        while ( (elem = results[i++]) ) {
            if ( elem === results[ i ] ) {
                j = duplicates.push( i );
            }
        }
        while ( j-- ) {
            results.splice( duplicates[ j ], 1 );
        }
    }

    return results;
};

/**
 * Utility function for retrieving the text value of an array of DOM nodes
 * @param {Array|Element} elem
 */
getText = Sizzle.getText = function( elem ) {
    var node,
        ret = "",
        i = 0,
        nodeType = elem.nodeType;

    if ( !nodeType ) {
        // If no nodeType, this is expected to be an array
        for ( ; (node = elem[i]); i++ ) {
            // Do not traverse comment nodes
            ret += getText( node );
        }
    } else if ( nodeType === 1 || nodeType === 9 || nodeType === 11 ) {
        // Use textContent for elements
        // innerText usage removed for consistency of new lines (see #11153)
        if ( typeof elem.textContent === "string" ) {
            return elem.textContent;
        } else {
            // Traverse its children
            for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
                ret += getText( elem );
            }
        }
    } else if ( nodeType === 3 || nodeType === 4 ) {
        return elem.nodeValue;
    }
    // Do not include comment or processing instruction nodes

    return ret;
};

Expr = Sizzle.selectors = {

    // Can be adjusted by the user
    cacheLength: 50,

    createPseudo: markFunction,

    match: matchExpr,

    attrHandle: {},

    find: {},

    relative: {
        ">": { dir: "parentNode", first: true },
        " ": { dir: "parentNode" },
        "+": { dir: "previousSibling", first: true },
        "~": { dir: "previousSibling" }
    },

    preFilter: {
        "ATTR": function( match ) {
            match[1] = match[1].replace( runescape, funescape );

            // Move the given value to match[3] whether quoted or unquoted
            match[3] = ( match[4] || match[5] || "" ).replace( runescape, funescape );

            if ( match[2] === "~=" ) {
                match[3] = " " + match[3] + " ";
            }

            return match.slice( 0, 4 );
        },

        "CHILD": function( match ) {
            /* matches from matchExpr["CHILD"]
                1 type (only|nth|...)
                2 what (child|of-type)
                3 argument (even|odd|\d*|\d*n([+-]\d+)?|...)
                4 xn-component of xn+y argument ([+-]?\d*n|)
                5 sign of xn-component
                6 x of xn-component
                7 sign of y-component
                8 y of y-component
            */
            match[1] = match[1].toLowerCase();

            if ( match[1].slice( 0, 3 ) === "nth" ) {
                // nth-* requires argument
                if ( !match[3] ) {
                    Sizzle.error( match[0] );
                }

                // numeric x and y parameters for Expr.filter.CHILD
                // remember that false/true cast respectively to 0/1
                match[4] = +( match[4] ? match[5] + (match[6] || 1) : 2 * ( match[3] === "even" || match[3] === "odd" ) );
                match[5] = +( ( match[7] + match[8] ) || match[3] === "odd" );

            // other types prohibit arguments
            } else if ( match[3] ) {
                Sizzle.error( match[0] );
            }

            return match;
        },

        "PSEUDO": function( match ) {
            var excess,
                unquoted = !match[5] && match[2];

            if ( matchExpr["CHILD"].test( match[0] ) ) {
                return null;
            }

            // Accept quoted arguments as-is
            if ( match[3] && match[4] !== undefined ) {
                match[2] = match[4];

            // Strip excess characters from unquoted arguments
            } else if ( unquoted && rpseudo.test( unquoted ) &&
                // Get excess from tokenize (recursively)
                (excess = tokenize( unquoted, true )) &&
                // advance to the next closing parenthesis
                (excess = unquoted.indexOf( ")", unquoted.length - excess ) - unquoted.length) ) {

                // excess is a negative index
                match[0] = match[0].slice( 0, excess );
                match[2] = unquoted.slice( 0, excess );
            }

            // Return only captures needed by the pseudo filter method (type and argument)
            return match.slice( 0, 3 );
        }
    },

    filter: {

        "TAG": function( nodeNameSelector ) {
            var nodeName = nodeNameSelector.replace( runescape, funescape ).toLowerCase();
            return nodeNameSelector === "*" ?
                function() { return true; } :
                function( elem ) {
                    return elem.nodeName && elem.nodeName.toLowerCase() === nodeName;
                };
        },

        "CLASS": function( className ) {
            var pattern = classCache[ className + " " ];

            return pattern ||
                (pattern = new RegExp( "(^|" + whitespace + ")" + className + "(" + whitespace + "|$)" )) &&
                classCache( className, function( elem ) {
                    return pattern.test( typeof elem.className === "string" && elem.className || typeof elem.getAttribute !== strundefined && elem.getAttribute("class") || "" );
                });
        },

        "ATTR": function( name, operator, check ) {
            return function( elem ) {
                var result = Sizzle.attr( elem, name );

                if ( result == null ) {
                    return operator === "!=";
                }
                if ( !operator ) {
                    return true;
                }

                result += "";

                return operator === "=" ? result === check :
                    operator === "!=" ? result !== check :
                    operator === "^=" ? check && result.indexOf( check ) === 0 :
                    operator === "*=" ? check && result.indexOf( check ) > -1 :
                    operator === "$=" ? check && result.slice( -check.length ) === check :
                    operator === "~=" ? ( " " + result + " " ).indexOf( check ) > -1 :
                    operator === "|=" ? result === check || result.slice( 0, check.length + 1 ) === check + "-" :
                    false;
            };
        },

        "CHILD": function( type, what, argument, first, last ) {
            var simple = type.slice( 0, 3 ) !== "nth",
                forward = type.slice( -4 ) !== "last",
                ofType = what === "of-type";

            return first === 1 && last === 0 ?

                // Shortcut for :nth-*(n)
                function( elem ) {
                    return !!elem.parentNode;
                } :

                function( elem, context, xml ) {
                    var cache, outerCache, node, diff, nodeIndex, start,
                        dir = simple !== forward ? "nextSibling" : "previousSibling",
                        parent = elem.parentNode,
                        name = ofType && elem.nodeName.toLowerCase(),
                        useCache = !xml && !ofType;

                    if ( parent ) {

                        // :(first|last|only)-(child|of-type)
                        if ( simple ) {
                            while ( dir ) {
                                node = elem;
                                while ( (node = node[ dir ]) ) {
                                    if ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) {
                                        return false;
                                    }
                                }
                                // Reverse direction for :only-* (if we haven't yet done so)
                                start = dir = type === "only" && !start && "nextSibling";
                            }
                            return true;
                        }

                        start = [ forward ? parent.firstChild : parent.lastChild ];

                        // non-xml :nth-child(...) stores cache data on `parent`
                        if ( forward && useCache ) {
                            // Seek `elem` from a previously-cached index
                            outerCache = parent[ expando ] || (parent[ expando ] = {});
                            cache = outerCache[ type ] || [];
                            nodeIndex = cache[0] === dirruns && cache[1];
                            diff = cache[0] === dirruns && cache[2];
                            node = nodeIndex && parent.childNodes[ nodeIndex ];

                            while ( (node = ++nodeIndex && node && node[ dir ] ||

                                // Fallback to seeking `elem` from the start
                                (diff = nodeIndex = 0) || start.pop()) ) {

                                // When found, cache indexes on `parent` and break
                                if ( node.nodeType === 1 && ++diff && node === elem ) {
                                    outerCache[ type ] = [ dirruns, nodeIndex, diff ];
                                    break;
                                }
                            }

                        // Use previously-cached element index if available
                        } else if ( useCache && (cache = (elem[ expando ] || (elem[ expando ] = {}))[ type ]) && cache[0] === dirruns ) {
                            diff = cache[1];

                        // xml :nth-child(...) or :nth-last-child(...) or :nth(-last)?-of-type(...)
                        } else {
                            // Use the same loop as above to seek `elem` from the start
                            while ( (node = ++nodeIndex && node && node[ dir ] ||
                                (diff = nodeIndex = 0) || start.pop()) ) {

                                if ( ( ofType ? node.nodeName.toLowerCase() === name : node.nodeType === 1 ) && ++diff ) {
                                    // Cache the index of each encountered element
                                    if ( useCache ) {
                                        (node[ expando ] || (node[ expando ] = {}))[ type ] = [ dirruns, diff ];
                                    }

                                    if ( node === elem ) {
                                        break;
                                    }
                                }
                            }
                        }

                        // Incorporate the offset, then check against cycle size
                        diff -= last;
                        return diff === first || ( diff % first === 0 && diff / first >= 0 );
                    }
                };
        },

        "PSEUDO": function( pseudo, argument ) {
            // pseudo-class names are case-insensitive
            // http://www.w3.org/TR/selectors/#pseudo-classes
            // Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
            // Remember that setFilters inherits from pseudos
            var args,
                fn = Expr.pseudos[ pseudo ] || Expr.setFilters[ pseudo.toLowerCase() ] ||
                    Sizzle.error( "unsupported pseudo: " + pseudo );

            // The user may use createPseudo to indicate that
            // arguments are needed to create the filter function
            // just as Sizzle does
            if ( fn[ expando ] ) {
                return fn( argument );
            }

            // But maintain support for old signatures
            if ( fn.length > 1 ) {
                args = [ pseudo, pseudo, "", argument ];
                return Expr.setFilters.hasOwnProperty( pseudo.toLowerCase() ) ?
                    markFunction(function( seed, matches ) {
                        var idx,
                            matched = fn( seed, argument ),
                            i = matched.length;
                        while ( i-- ) {
                            idx = indexOf.call( seed, matched[i] );
                            seed[ idx ] = !( matches[ idx ] = matched[i] );
                        }
                    }) :
                    function( elem ) {
                        return fn( elem, 0, args );
                    };
            }

            return fn;
        }
    },

    pseudos: {
        // Potentially complex pseudos
        "not": markFunction(function( selector ) {
            // Trim the selector passed to compile
            // to avoid treating leading and trailing
            // spaces as combinators
            var input = [],
                results = [],
                matcher = compile( selector.replace( rtrim, "$1" ) );

            return matcher[ expando ] ?
                markFunction(function( seed, matches, context, xml ) {
                    var elem,
                        unmatched = matcher( seed, null, xml, [] ),
                        i = seed.length;

                    // Match elements unmatched by `matcher`
                    while ( i-- ) {
                        if ( (elem = unmatched[i]) ) {
                            seed[i] = !(matches[i] = elem);
                        }
                    }
                }) :
                function( elem, context, xml ) {
                    input[0] = elem;
                    matcher( input, null, xml, results );
                    return !results.pop();
                };
        }),

        "has": markFunction(function( selector ) {
            return function( elem ) {
                return Sizzle( selector, elem ).length > 0;
            };
        }),

        "contains": markFunction(function( text ) {
            return function( elem ) {
                return ( elem.textContent || elem.innerText || getText( elem ) ).indexOf( text ) > -1;
            };
        }),

        // "Whether an element is represented by a :lang() selector
        // is based solely on the element's language value
        // being equal to the identifier C,
        // or beginning with the identifier C immediately followed by "-".
        // The matching of C against the element's language value is performed case-insensitively.
        // The identifier C does not have to be a valid language name."
        // http://www.w3.org/TR/selectors/#lang-pseudo
        "lang": markFunction( function( lang ) {
            // lang value must be a valid identifier
            if ( !ridentifier.test(lang || "") ) {
                Sizzle.error( "unsupported lang: " + lang );
            }
            lang = lang.replace( runescape, funescape ).toLowerCase();
            return function( elem ) {
                var elemLang;
                do {
                    if ( (elemLang = documentIsHTML ?
                        elem.lang :
                        elem.getAttribute("xml:lang") || elem.getAttribute("lang")) ) {

                        elemLang = elemLang.toLowerCase();
                        return elemLang === lang || elemLang.indexOf( lang + "-" ) === 0;
                    }
                } while ( (elem = elem.parentNode) && elem.nodeType === 1 );
                return false;
            };
        }),

        // Miscellaneous
        "target": function( elem ) {
            var hash = window.location && window.location.hash;
            return hash && hash.slice( 1 ) === elem.id;
        },

        "root": function( elem ) {
            return elem === docElem;
        },

        "focus": function( elem ) {
            return elem === document.activeElement && (!document.hasFocus || document.hasFocus()) && !!(elem.type || elem.href || ~elem.tabIndex);
        },

        // Boolean properties
        "enabled": function( elem ) {
            return elem.disabled === false;
        },

        "disabled": function( elem ) {
            return elem.disabled === true;
        },

        "checked": function( elem ) {
            // In CSS3, :checked should return both checked and selected elements
            // http://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
            var nodeName = elem.nodeName.toLowerCase();
            return (nodeName === "input" && !!elem.checked) || (nodeName === "option" && !!elem.selected);
        },

        "selected": function( elem ) {
            // Accessing this property makes selected-by-default
            // options in Safari work properly
            if ( elem.parentNode ) {
                elem.parentNode.selectedIndex;
            }

            return elem.selected === true;
        },

        // Contents
        "empty": function( elem ) {
            // http://www.w3.org/TR/selectors/#empty-pseudo
            // :empty is only affected by element nodes and content nodes(including text(3), cdata(4)),
            //   not comment, processing instructions, or others
            // Thanks to Diego Perini for the nodeName shortcut
            //   Greater than "@" means alpha characters (specifically not starting with "#" or "?")
            for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
                if ( elem.nodeName > "@" || elem.nodeType === 3 || elem.nodeType === 4 ) {
                    return false;
                }
            }
            return true;
        },

        "parent": function( elem ) {
            return !Expr.pseudos["empty"]( elem );
        },

        // Element/input types
        "header": function( elem ) {
            return rheader.test( elem.nodeName );
        },

        "input": function( elem ) {
            return rinputs.test( elem.nodeName );
        },

        "button": function( elem ) {
            var name = elem.nodeName.toLowerCase();
            return name === "input" && elem.type === "button" || name === "button";
        },

        "text": function( elem ) {
            var attr;
            // IE6 and 7 will map elem.type to 'text' for new HTML5 types (search, etc)
            // use getAttribute instead to test this case
            return elem.nodeName.toLowerCase() === "input" &&
                elem.type === "text" &&
                ( (attr = elem.getAttribute("type")) == null || attr.toLowerCase() === elem.type );
        },

        // Position-in-collection
        "first": createPositionalPseudo(function() {
            return [ 0 ];
        }),

        "last": createPositionalPseudo(function( matchIndexes, length ) {
            return [ length - 1 ];
        }),

        "eq": createPositionalPseudo(function( matchIndexes, length, argument ) {
            return [ argument < 0 ? argument + length : argument ];
        }),

        "even": createPositionalPseudo(function( matchIndexes, length ) {
            var i = 0;
            for ( ; i < length; i += 2 ) {
                matchIndexes.push( i );
            }
            return matchIndexes;
        }),

        "odd": createPositionalPseudo(function( matchIndexes, length ) {
            var i = 1;
            for ( ; i < length; i += 2 ) {
                matchIndexes.push( i );
            }
            return matchIndexes;
        }),

        "lt": createPositionalPseudo(function( matchIndexes, length, argument ) {
            var i = argument < 0 ? argument + length : argument;
            for ( ; --i >= 0; ) {
                matchIndexes.push( i );
            }
            return matchIndexes;
        }),

        "gt": createPositionalPseudo(function( matchIndexes, length, argument ) {
            var i = argument < 0 ? argument + length : argument;
            for ( ; ++i < length; ) {
                matchIndexes.push( i );
            }
            return matchIndexes;
        })
    }
};

Expr.pseudos["nth"] = Expr.pseudos["eq"];

// Add button/input type pseudos
for ( i in { radio: true, checkbox: true, file: true, password: true, image: true } ) {
    Expr.pseudos[ i ] = createInputPseudo( i );
}
for ( i in { submit: true, reset: true } ) {
    Expr.pseudos[ i ] = createButtonPseudo( i );
}

// Easy API for creating new setFilters
function setFilters() {}
setFilters.prototype = Expr.filters = Expr.pseudos;
Expr.setFilters = new setFilters();

//词法分析器(tokenize)
//假设传入进来的选择器是:div > p + .aaron[type="checkbox"], #id:first-child
//这里可以分为两个规则:div > p + .aaron[type="checkbox"] 以及 #id:first-child
//返回的需要是一个Token序列
//Sizzle的Token格式如下 :{value:'匹配到的字符串', type:'对应的Token类型', matches:'正则匹配到的一个结构'}
function tokenize( selector, parseOnly ) {
    var matched, match, tokens, type,
        soFar, groups, preFilters,
        //tokenize函数中获取缓存
        cached = tokenCache[ selector + " " ];

        //这里的soFar是表示目前还未分析的字符串剩余部分
  //groups表示目前已经匹配到的规则组,在这个例子里边,groups的长度最后是2,存放的是每个规则对应的Token序列

    //如果cache里边有,直接拿出来即可

    if ( cached ) {
        return parseOnly ? 0 : cached.slice( 0 );
    }
//初始化
    soFar = selector;
    groups = [];//这是最后要返回的结果,一个二维数组
    //比如"title,div > :nth-child(even)"解析下面的符号流
    // [ [{value:"title",type:"TAG",matches:["title"]}],
    //   [{value:"div",type:["TAG",matches:["div"]},
    //    {value:">", type: ">"},
    //    {value:":nth-child(even)",type:"CHILD",matches:["nth",
    //     "child","even",2,0,undefined,undefined,undefined]}
    //   ]
    // ]
    //有多少个并联选择器,里面就有多少个数组,数组里面是拥有value与type的对象

    //这里的预处理器为了对匹配到的Token适当做一些调整
    //自行查看源码,其实就是正则匹配到的内容的一个预处理
    preFilters = Expr.preFilter;
//递归检测字符串
    //比如"div > p + .aaron input[type="checkbox"]"
    while ( soFar ) {

        // Comma and first run
        // 以第一个逗号切割选择符,然后去掉前面的部分
        if ( !matched || (match = rcomma.exec( soFar )) ) {
            if ( match ) {
                // Don't consume trailing commas as valid
                //如果匹配到逗号
                soFar = soFar.slice( match[0].length ) || soFar;
            }
            //往规则组里边压入一个Token序列,目前Token序列还是空的
            groups.push( tokens = [] );
        }

        matched = false;
        // Combinators
        //将刚才前面的部分以关系选择器再进行划分
        //先处理这几个特殊的Token : >, +, 空格, ~
        //因为他们比较简单,并且是单字符的

        // Combinators
        if ( (match = rcombinators.exec( soFar )) ) {
            //获取到匹配的字符
            matched = match.shift();
            //放入Token序列中
            tokens.push({
                value: matched,
                // Cast descendant combinators to space
                type: match[0].replace( rtrim, " " )
            });
            //剩余还未分析的字符串需要减去这段已经分析过的
            soFar = soFar.slice( matched.length );
        }

        // Filters
        // Filters
        //这里开始分析这几种Token : TAG, ID, CLASS, ATTR, CHILD, PSEUDO, NAME
        //将每个选择器组依次用ID,TAG,CLASS,ATTR,CHILD,PSEUDO这些正则进行匹配
        //Expr.filter里边对应地 就有这些key
    /**
     *
     *
     *matchExpr 过滤正则
        ATTR: /^\[[\x20\t\r\n\f]*((?:\\.|[\w-]|[^\x00-\xa0])+)[\x20\t\r\n\f]*(?:([*^$|!~]?=)[\x20\t\r\n\f]*(?:(['"])((?:\\.|[^\\])*?)\3|((?:\\.|[\w#-]|[^\x00-\xa0])+)|)|)[\x20\t\r\n\f]*\]/
        CHILD: /^:(only|first|last|nth|nth-last)-(child|of-type)(?:\([\x20\t\r\n\f]*(even|odd|(([+-]|)(\d*)n|)[\x20\t\r\n\f]*(?:([+-]|)[\x20\t\r\n\f]*(\d+)|))[\x20\t\r\n\f]*\)|)/i
        CLASS: /^\.((?:\\.|[\w-]|[^\x00-\xa0])+)/
        ID: /^#((?:\\.|[\w-]|[^\x00-\xa0])+)/
        PSEUDO: /^:((?:\\.|[\w-]|[^\x00-\xa0])+)(?:\(((['"])((?:\\.|[^\\])*?)\3|((?:\\.|[^\\()[\]]|\[[\x20\t\r\n\f]*((?:\\.|[\w-]|[^\x00-\xa0])+)[\x20\t\r\n\f]*(?:([*^$|!~]?=)[\x20\t\r\n\f]*(?:(['"])((?:\\.|[^\\])*?)\8|((?:\\.|[\w#-]|[^\x00-\xa0])+)|)|)[\x20\t\r\n\f]*\])*)|.*)\)|)/
        TAG: /^((?:\\.|[\w*-]|[^\x00-\xa0])+)/
        bool: /^(?:checked|selected|async|autofocus|autoplay|controls|defer|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped)$/i
        needsContext: /^[\x20\t\r\n\f]*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\([\x20\t\r\n\f]*((?:-\d)?\d*)[\x20\t\r\n\f]*\)|)(?=[^-]|$)/i
     *
     */
        //如果通过正则匹配到了Token格式:match = matchExpr[ type ].exec( soFar )
        //然后看看需不需要预处理:!preFilters[ type ]
        //如果需要 ,那么通过预处理器将匹配到的处理一下 : match = preFilters[ type ]( match )
        for ( type in Expr.filter ) {
            if ( (match = matchExpr[ type ].exec( soFar )) && (!preFilters[ type ] ||
                (match = preFilters[ type ]( match ))) ) {
                matched = match.shift();
                //放入Token序列中
                tokens.push({
                    value: matched,
                    type: type,
                    matches: match
                });
                //剩余还未分析的字符串需要减去这段已经分析过的
                soFar = soFar.slice( matched.length );
            }
        }
//如果到了这里都还没matched到,那么说明这个选择器在这里有错误
            //直接中断词法分析过程
           //这就是Sizzle对词法分析的异常处理
        if ( !matched ) {
            break;
        }
    }

    // Return the length of the invalid excess
    // if we're just parsing
    // Otherwise, throw an error or return tokens
    // Return the length of the invalid excess
    // if we're just parsing
    // Otherwise, throw an error or return tokens
    //放到tokenCache函数里进行缓存
    //如果只需要这个接口检查选择器的合法性,直接就返回soFar的剩余长度,倘若是大于零,说明选择器不合法
    //其余情况,如果soFar长度大于零,抛出异常;否则把groups记录在cache里边并返回,
    return parseOnly ?
        soFar.length :
        soFar ?
            Sizzle.error( selector ) :
            // Cache the tokens //设置缓存
            tokenCache( selector, groups ).slice( 0 );
}

function toSelector( tokens ) {
    var i = 0,
        len = tokens.length,
        selector = "";
    for ( ; i < len; i++ ) {
        selector += tokens[i].value;
    }
    return selector;
}

function addCombinator( matcher, combinator, base ) {
    var dir = combinator.dir,
        checkNonElements = base && dir === "parentNode",
        doneName = done++;

    return combinator.first ?
        // Check against closest ancestor/preceding element
        function( elem, context, xml ) {
            while ( (elem = elem[ dir ]) ) {
                if ( elem.nodeType === 1 || checkNonElements ) {
                    return matcher( elem, context, xml );
                }
            }
        } :

        // Check against all ancestor/preceding elements
        function( elem, context, xml ) {
            var data, cache, outerCache,
                dirkey = dirruns + " " + doneName;

            // We can't set arbitrary data on XML nodes, so they don't benefit from dir caching
            if ( xml ) {
                while ( (elem = elem[ dir ]) ) {
                    if ( elem.nodeType === 1 || checkNonElements ) {
                        if ( matcher( elem, context, xml ) ) {
                            return true;
                        }
                    }
                }
            } else {
                while ( (elem = elem[ dir ]) ) {
                    if ( elem.nodeType === 1 || checkNonElements ) {
                        outerCache = elem[ expando ] || (elem[ expando ] = {});
                        if ( (cache = outerCache[ dir ]) && cache[0] === dirkey ) {
                            if ( (data = cache[1]) === true || data === cachedruns ) {
                                return data === true;
                            }
                        } else {
                            cache = outerCache[ dir ] = [ dirkey ];
                            cache[1] = matcher( elem, context, xml ) || cachedruns;
                            if ( cache[1] === true ) {
                                return true;
                            }
                        }
                    }
                }
            }
        };
}

function elementMatcher( matchers ) {
    return matchers.length > 1 ?
        function( elem, context, xml ) {
            var i = matchers.length;
            while ( i-- ) {
                if ( !matchers[i]( elem, context, xml ) ) {
                    return false;
                }
            }
            return true;
        } :
        matchers[0];
}

function condense( unmatched, map, filter, context, xml ) {
    var elem,
        newUnmatched = [],
        i = 0,
        len = unmatched.length,
        mapped = map != null;

    for ( ; i < len; i++ ) {
        if ( (elem = unmatched[i]) ) {
            if ( !filter || filter( elem, context, xml ) ) {
                newUnmatched.push( elem );
                if ( mapped ) {
                    map.push( i );
                }
            }
        }
    }

    return newUnmatched;
}

function setMatcher( preFilter, selector, matcher, postFilter, postFinder, postSelector ) {
    if ( postFilter && !postFilter[ expando ] ) {
        postFilter = setMatcher( postFilter );
    }
    if ( postFinder && !postFinder[ expando ] ) {
        postFinder = setMatcher( postFinder, postSelector );
    }
    return markFunction(function( seed, results, context, xml ) {
        var temp, i, elem,
            preMap = [],
            postMap = [],
            preexisting = results.length,

            // Get initial elements from seed or context
            elems = seed || multipleContexts( selector || "*", context.nodeType ? [ context ] : context, [] ),

            // Prefilter to get matcher input, preserving a map for seed-results synchronization
            matcherIn = preFilter && ( seed || !selector ) ?
                condense( elems, preMap, preFilter, context, xml ) :
                elems,

            matcherOut = matcher ?
                // If we have a postFinder, or filtered seed, or non-seed postFilter or preexisting results,
                postFinder || ( seed ? preFilter : preexisting || postFilter ) ?

                    // ...intermediate processing is necessary
                    [] :

                    // ...otherwise use results directly
                    results :
                matcherIn;

        // Find primary matches
        if ( matcher ) {
            matcher( matcherIn, matcherOut, context, xml );
        }

        // Apply postFilter
        if ( postFilter ) {
            temp = condense( matcherOut, postMap );
            postFilter( temp, [], context, xml );

            // Un-match failing elements by moving them back to matcherIn
            i = temp.length;
            while ( i-- ) {
                if ( (elem = temp[i]) ) {
                    matcherOut[ postMap[i] ] = !(matcherIn[ postMap[i] ] = elem);
                }
            }
        }

        if ( seed ) {
            if ( postFinder || preFilter ) {
                if ( postFinder ) {
                    // Get the final matcherOut by condensing this intermediate into postFinder contexts
                    temp = [];
                    i = matcherOut.length;
                    while ( i-- ) {
                        if ( (elem = matcherOut[i]) ) {
                            // Restore matcherIn since elem is not yet a final match
                            temp.push( (matcherIn[i] = elem) );
                        }
                    }
                    postFinder( null, (matcherOut = []), temp, xml );
                }

                // Move matched elements from seed to results to keep them synchronized
                i = matcherOut.length;
                while ( i-- ) {
                    if ( (elem = matcherOut[i]) &&
                        (temp = postFinder ? indexOf.call( seed, elem ) : preMap[i]) > -1 ) {

                        seed[temp] = !(results[temp] = elem);
                    }
                }
            }

        // Add elements to results, through postFinder if defined
        } else {
            matcherOut = condense(
                matcherOut === results ?
                    matcherOut.splice( preexisting, matcherOut.length ) :
                    matcherOut
            );
            if ( postFinder ) {
                postFinder( null, results, matcherOut, xml );
            } else {
                push.apply( results, matcherOut );
            }
        }
    });
}

function matcherFromTokens( tokens ) {
    var checkContext, matcher, j,
        len = tokens.length,
        leadingRelative = Expr.relative[ tokens[0].type ],
        implicitRelative = leadingRelative || Expr.relative[" "],
        i = leadingRelative ? 1 : 0,

        // The foundational matcher ensures that elements are reachable from top-level context(s)
        matchContext = addCombinator( function( elem ) {
            return elem === checkContext;
        }, implicitRelative, true ),
        matchAnyContext = addCombinator( function( elem ) {
            return indexOf.call( checkContext, elem ) > -1;
        }, implicitRelative, true ),
        matchers = [ function( elem, context, xml ) {
            return ( !leadingRelative && ( xml || context !== outermostContext ) ) || (
                (checkContext = context).nodeType ?
                    matchContext( elem, context, xml ) :
                    matchAnyContext( elem, context, xml ) );
        } ];

    for ( ; i < len; i++ ) {
        if ( (matcher = Expr.relative[ tokens[i].type ]) ) {
            matchers = [ addCombinator(elementMatcher( matchers ), matcher) ];
        } else {
            matcher = Expr.filter[ tokens[i].type ].apply( null, tokens[i].matches );

            // Return special upon seeing a positional matcher
            if ( matcher[ expando ] ) {
                // Find the next relative operator (if any) for proper handling
                j = ++i;
                for ( ; j < len; j++ ) {
                    if ( Expr.relative[ tokens[j].type ] ) {
                        break;
                    }
                }
                return setMatcher(
                    i > 1 && elementMatcher( matchers ),
                    i > 1 && toSelector(
                        // If the preceding token was a descendant combinator, insert an implicit any-element `*`
                        tokens.slice( 0, i - 1 ).concat({ value: tokens[ i - 2 ].type === " " ? "*" : "" })
                    ).replace( rtrim, "$1" ),
                    matcher,
                    i < j && matcherFromTokens( tokens.slice( i, j ) ),
                    j < len && matcherFromTokens( (tokens = tokens.slice( j )) ),
                    j < len && toSelector( tokens )
                );
            }
            matchers.push( matcher );
        }
    }

    return elementMatcher( matchers );
}

function matcherFromGroupMatchers( elementMatchers, setMatchers ) {
    // A counter to specify which element is currently being matched
    var matcherCachedRuns = 0,
        bySet = setMatchers.length > 0,
        byElement = elementMatchers.length > 0,
        superMatcher = function( seed, context, xml, results, expandContext ) {
            var elem, j, matcher,
                setMatched = [],
                matchedCount = 0,
                i = "0",
                unmatched = seed && [],
                outermost = expandContext != null,
                contextBackup = outermostContext,
                // We must always have either seed elements or context
                elems = seed || byElement && Expr.find["TAG"]( "*", expandContext && context.parentNode || context ),
                // Use integer dirruns iff this is the outermost matcher
                dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1);

            if ( outermost ) {
                outermostContext = context !== document && context;
                cachedruns = matcherCachedRuns;
            }

            // Add elements passing elementMatchers directly to results
            // Keep `i` a string if there are no elements so `matchedCount` will be "00" below
            for ( ; (elem = elems[i]) != null; i++ ) {
                if ( byElement && elem ) {
                    j = 0;
                    while ( (matcher = elementMatchers[j++]) ) {
                        if ( matcher( elem, context, xml ) ) {
                            results.push( elem );
                            break;
                        }
                    }
                    if ( outermost ) {
                        dirruns = dirrunsUnique;
                        cachedruns = ++matcherCachedRuns;
                    }
                }

                // Track unmatched elements for set filters
                if ( bySet ) {
                    // They will have gone through all possible matchers
                    if ( (elem = !matcher && elem) ) {
                        matchedCount--;
                    }

                    // Lengthen the array for every element, matched or not
                    if ( seed ) {
                        unmatched.push( elem );
                    }
                }
            }

            // Apply set filters to unmatched elements
            matchedCount += i;
            if ( bySet && i !== matchedCount ) {
                j = 0;
                while ( (matcher = setMatchers[j++]) ) {
                    matcher( unmatched, setMatched, context, xml );
                }

                if ( seed ) {
                    // Reintegrate element matches to eliminate the need for sorting
                    if ( matchedCount > 0 ) {
                        while ( i-- ) {
                            if ( !(unmatched[i] || setMatched[i]) ) {
                                setMatched[i] = pop.call( results );
                            }
                        }
                    }

                    // Discard index placeholder values to get only actual matches
                    setMatched = condense( setMatched );
                }

                // Add matches to results
                push.apply( results, setMatched );

                // Seedless set matches succeeding multiple successful matchers stipulate sorting
                if ( outermost && !seed && setMatched.length > 0 &&
                    ( matchedCount + setMatchers.length ) > 1 ) {

                    Sizzle.uniqueSort( results );
                }
            }

            // Override manipulation of globals by nested matchers
            if ( outermost ) {
                dirruns = dirrunsUnique;
                outermostContext = contextBackup;
            }

            return unmatched;
        };

    return bySet ?
        markFunction( superMatcher ) :
        superMatcher;
}

compile = Sizzle.compile = function( selector, group /* Internal Use Only */ ) {
    var i,
        setMatchers = [],
        elementMatchers = [],
        cached = compilerCache[ selector + " " ];

    if ( !cached ) {
        // Generate a function of recursive functions that can be used to check each element
        if ( !group ) {
            group = tokenize( selector );
        }
        i = group.length;
        while ( i-- ) {
            cached = matcherFromTokens( group[i] );
            if ( cached[ expando ] ) {
                setMatchers.push( cached );
            } else {
                elementMatchers.push( cached );
            }
        }

        // Cache the compiled function
        cached = compilerCache( selector, matcherFromGroupMatchers( elementMatchers, setMatchers ) );
    }
    return cached;
};

function multipleContexts( selector, contexts, results ) {
    var i = 0,
        len = contexts.length;
    for ( ; i < len; i++ ) {
        Sizzle( selector, contexts[i], results );
    }
    return results;
}

//引擎的主要入口函数
    function select(selector, context, results, seed) {
        var i, tokens, token, type, find,
            //解析出词法格式
            match = tokenize(selector);

        if (!seed) { //如果外界没有指定初始集合seed了。
            // Try to minimize operations if there is only one group
            // 没有多组的情况下
            // 如果只是单个选择器的情况,也即是没有逗号的情况:div, p,可以特殊优化一下
            if (match.length === 1) {

                // Take a shortcut and set the context if the root selector is an ID
                tokens = match[0] = match[0].slice(0); //取出选择器Token序列

                //如果第一个是selector是id我们可以设置context快速查找
                if (tokens.length > 2 && (token = tokens[0]).type === "ID" &&
                    support.getById && context.nodeType === 9 && documentIsHTML &&
                    Expr.relative[tokens[1].type]) {

                    context = (Expr.find["ID"](token.matches[0].replace(runescape, funescape), context) || [])[0];
                    if (!context) {
                        //如果context这个元素(selector第一个id选择器)都不存在就不用查找了
                        return results;
                    }
                    //去掉第一个id选择器
                    selector = selector.slice(tokens.shift().value.length);
                }

                // Fetch a seed set for right-to-left matching
                //其中: "needsContext"= new RegExp( "^" + whitespace + "*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" + whitespace + "*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
                //即是表示如果没有一些结构伪类,这些是需要用另一种方式过滤,在之后文章再详细剖析。
                //那么就从最后一条规则开始,先找出seed集合
                i = matchExpr["needsContext"].test(selector) ? 0 : tokens.length;

                //从右向左边查询
                while (i--) { //从后开始向前找!
                    token = tokens[i]; //找到后边的规则

                    // Abort if we hit a combinator
                    // 如果遇到了关系选择器中止
                    //
                    //  > + ~ 空
                    //
                    if (Expr.relative[(type = token.type)]) {
                        break;
                    }

                    /*
                  先看看有没有搜索器find,搜索器就是浏览器一些原生的取DOM接口,简单的表述就是以下对象了
                  Expr.find = {
                    'ID'    : context.getElementById,
                    'CLASS' : context.getElementsByClassName,
                    'NAME'  : context.getElementsByName,
                    'TAG'   : context.getElementsByTagName
                  }
                */
                    //如果是:first-child这类伪类就没有对应的搜索器了,此时会向前提取前一条规则token
                    if ((find = Expr.find[type])) {

                        // Search, expanding context for leading sibling combinators
                        // 尝试一下能否通过这个搜索器搜到符合条件的初始集合seed
                        if ((seed = find(
                            token.matches[0].replace(runescape, funescape),
                            rsibling.test(tokens[0].type) && context.parentNode || context
                        ))) {

                            //如果真的搜到了
                            // If seed is empty or no tokens remain, we can return early
                            //把最后一条规则去除掉
                            tokens.splice(i, 1);
                            selector = seed.length && toSelector(tokens);

                            //看看当前剩余的选择器是否为空
                            if (!selector) {
                                //是的话,提前返回结果了。
                                push.apply(results, seed);
                                return results;
                            }

                            //已经找到了符合条件的seed集合,此时前边还有其他规则,跳出去
                            break;
                        }
                    }
                }
            }
        }


        // "div > p + div.aaron [type="checkbox"]"

        // Compile and execute a filtering function
        // Provide `match` to avoid retokenization if we modified the selector above
        // 交由compile来生成一个称为终极匹配器
        // 通过这个匹配器过滤seed,把符合条件的结果放到results里边
        //
        //    //生成编译函数
        //  var superMatcher =   compile( selector, match )
        //
        //  //执行
        //    superMatcher(seed,context,!documentIsHTML,results,rsibling.test( selector ))
        //
        compile(selector, match)(
            seed,
            context, !documentIsHTML,
            results,
            rsibling.test(selector)
        );
        return results;
    }

// One-time assignments

// Sort stability
support.sortStable = expando.split("").sort( sortOrder ).join("") === expando;

// Support: Chrome<14
// Always assume duplicates if they aren't passed to the comparison function
support.detectDuplicates = hasDuplicate;

// Initialize against the default document
setDocument();

// Support: Webkit<537.32 - Safari 6.0.3/Chrome 25 (fixed in Chrome 27)
// Detached nodes confoundingly follow *each other*
support.sortDetached = assert(function( div1 ) {
    // Should return 1, but returns 4 (following)
    return div1.compareDocumentPosition( document.createElement("div") ) & 1;
});

// Support: IE<8
// Prevent attribute/property "interpolation"
// http://msdn.microsoft.com/en-us/library/ms536429%28VS.85%29.aspx
if ( !assert(function( div ) {
    div.innerHTML = "<a href='#'></a>";
    return div.firstChild.getAttribute("href") === "#" ;
}) ) {
    addHandle( "type|href|height|width", function( elem, name, isXML ) {
        if ( !isXML ) {
            return elem.getAttribute( name, name.toLowerCase() === "type" ? 1 : 2 );
        }
    });
}

// Support: IE<9
// Use defaultValue in place of getAttribute("value")
if ( !support.attributes || !assert(function( div ) {
    div.innerHTML = "<input/>";
    div.firstChild.setAttribute( "value", "" );
    return div.firstChild.getAttribute( "value" ) === "";
}) ) {
    addHandle( "value", function( elem, name, isXML ) {
        if ( !isXML && elem.nodeName.toLowerCase() === "input" ) {
            return elem.defaultValue;
        }
    });
}

// Support: IE<9
// Use getAttributeNode to fetch booleans when getAttribute lies
if ( !assert(function( div ) {
    return div.getAttribute("disabled") == null;
}) ) {
    addHandle( booleans, function( elem, name, isXML ) {
        var val;
        if ( !isXML ) {
            return (val = elem.getAttributeNode( name )) && val.specified ?
                val.value :
                elem[ name ] === true ? name.toLowerCase() : null;
        }
    });
}

jQuery.find = Sizzle;
jQuery.expr = Sizzle.selectors;
jQuery.expr[":"] = jQuery.expr.pseudos;
jQuery.unique = Sizzle.uniqueSort;
jQuery.text = Sizzle.getText;
jQuery.isXMLDoc = Sizzle.isXML;
jQuery.contains = Sizzle.contains;


})( window );
// String to Object options format cache
var optionsCache = {};

/*
optionsCache和options的关系是下面这样的:
options:{once:true,memory:true}
optionCache:{'once memory':{once:true,memory:true}}
*/

// Convert String-formatted options into Object-formatted ones and store in cache
function createOptions( options ) {
    // 多个变量指向同一对象(或数组)引用时,其中一个变量修改了被引用对象的内部结构,其他引用变量也会表现出来
    var object = optionsCache[ options ] = {};//这里是一个指针引用,两个对象指向同一个地方,所以给object赋值等同于给optionsCache赋值
    //core_rnotwhite是匹配单词的
    jQuery.each( options.match( core_rnotwhite ) || [], function( _, flag ) {
        object[ flag ] = true;
    });
    return object;
}

/*
 * Create a callback list using the following parameters:
 *
 *    options: an optional list of space-separated options that will change how
 *            the callback list behaves or a more traditional option object
 *
 * By default a callback list will act like an event callback list and can be
 * "fired" multiple times.
 *
 * Possible options:
 *
 *    once:            will ensure the callback list can only be fired once (like a Deferred)
 *
 *    memory:            will keep track of previous values and will call any callback added
 *                    after the list has been fired right away with the latest "memorized"
 *                    values (like a Deferred)
 /*
 memory:
 function fn1( value ) {
    console.log( value );
}

function fn2( value ) {
    fn1("fn2 says: " + value);
    return false;
}
var callbacks = $.Callbacks("memory");

callbacks.add( fn1 );
callbacks.fire( "1" );

VM171:2 1
Object {}
callbacks.add( fn1 );
callbacks.fire( "2" );
VM171:2 1
2VM171:2 2
Object {}
callbacks.add( fn1 );
callbacks.fire( "3" );
VM171:2 2
3VM171:2 3
Object {}
callbacks.add( fn1 );
callbacks.fire( "4" );
VM171:2 3
4VM171:2 4
Object {}
 */
 *
 *    unique:            will ensure a callback can only be added once (no duplicate in the list)
 *
 *    stopOnFalse:    interrupt callings when a callback returns false//设计在内部方法fire执行时的for循环上
 *
 */
 /*
 * once: 确保回调列表仅只fire一次,设计在内部方法fire执行时的for循环上
 * unique: 在执行add操作中,确保回调列表中不存在重复的回调,设计在add上
 * stopOnFalse: 当执行回调返回值为false,则终止回调队列的执行
 * momery: 记录上一次fire时的参数,并在add中传递给fire和执行fire,执行时firingIndex为上一次fire时的firingLength memory方法就比较特殊了, 有点类似deferred的感觉,就是能够等全部的add都加载完毕后才触发
           memory的实现思路就是在add的时候直接触发fire,从而再次执行list列表,设计在add上
 */
 //还有需要注意的是,如果回调函数中使用了 this 对象,可以直接用这个 this 来访问self对象的公有API。当然,也可以用 fireWith() 自己指定 this 的引用对象。
 //jQuery.Callbacks()的核心思想是 Pub/Sub 模式,建立了程序间的松散耦合和高效通信。
jQuery.Callbacks = function( options ) {

    // Convert options from String-formatted to Object-formatted if needed
    // (we check in cache first)
     // 缓存所有的参数标志,当再次传递已传递过的参数标志,则使用缓存值optionsCache[ options ]
     //通过字符串在optionsCache寻找有没有相应缓存,如果没有则创建一个,有则引用
    //如果是对象则通过jQuery.extend深复制后赋给options。
    //optionsCache[ options ]是说明如果有缓存则先走缓存
    //通过字符串在optionsCache寻找有没有相应缓存,如果没有则创建一个,有则引用
    //如果是对象则通过jQuery.extend深复制后赋给options。
    options = typeof options === "string" ?
       //处理单一参数或者组合参数的情况“once”  “once memory”,optionsCache[ options ]是如果之前存过的话就先走缓存
        ( optionsCache[ options ] || createOptions( options ) ) :
        // 说明也可以这样$.Callbacks({once:true, memory:true})使用
        jQuery.extend( {}, options );//什么情况下不是字符串呢,就是默认情况下,无参数,这typeof options="undefined",则便会执行这句话,主要目的是返回空字符串,防止出错

    var // Last fire value (for non-forgettable lists)
        memory,// 最后一次触发回调时传的参数 保持以前的值,将添加到这个列表的后面的最新的值立即执行调用任何回调 (像一个递延 Deferred).
        // Flag to know if list was already fired
        fired,// 列表中的函数是否已经回调至少一次
        // Flag to know if list is currently firing
        firing,// 列表中的函数是否正在回调中
        // First callback to fire (used internally by add and fireWith)
        firingStart,// 回调的起点
        // End of the loop when firing
        firingLength,// 回调时的循环结尾
        // Index of currently firing callback (modified by remove if needed)
        firingIndex,// 当前正在回调的函数索引
        // Actual callback list
        list = [],// 回调函数列表
        // Stack of fire calls for repeatable lists
        stack = !options.once && [],// 可重复的回调函数堆栈,用于控制触发回调时的参数列表
        // Fire callbacks data为fireWith内部整理的args数组
        fire = function( data ) {//用给定的参数调用所有的回调
            //如果参数memory为true,则记录data
            memory = options.memory && data;
            fired = true;//标记触发回调
            处理在add中,options.memory = true;的情况
            firingIndex = firingStart || 0;
            firingStart = 0;
            firingLength = list.length;
            //标记正在触发回调
            firing = true;
            //进行for循环 
            for ( ; list && firingIndex < firingLength; firingIndex++ ) {
                // 正在执行的回调返回值为false 且 options.stopOnFalse为true,则终止回调队列的执行
                // 阻止未来可能由于add所产生的回调
                if ( list[ firingIndex ].apply( data[ 0 ], data[ 1 ] ) === false && options.stopOnFalse ) {
                    memory = false; // To prevent further calls using add
                    break;// 阻止未来可能由于add所产生的回调
                }
            }
            //标记回调结束
            firing = false;
            if ( list ) {
                // 处理正在执行的回调中执行fireWith的操作;
                if ( stack ) {
                    if ( stack.length ) {
                        //从堆栈头部取出,递归fire
                        fire( stack.shift() );
                    }
                    // 上一分支状态为回调执行过,且可以执行多次
          // 此时 options.once = true; 这里将list设置为[],只是确保下次执行fire时,无回调执行
          // 但是如果 options.memory = true; 仍然会执行add中的fire操作,因为此时回调列表中已有回调
                } else if ( memory ) {//否则,如果有记忆
                    list = [];
                } else {//再否则阻止回调列表中的回调
                    self.disable();
                }
            }
        },
        // Actual Callbacks object
        // 暴露在外的Callbacks对象,对外接口
        //外观模式 self.fire –> self.fireWith –> fire
        /*

        var f1 = function() {
    console.log("f1");
    return false
  }; //注意 return false;
  var f2 = function() {
    console.log("f2");
  };

  var callbacks = $.Callbacks();
  callbacks.add(f1);
  callbacks.add(f2);
  callbacks.fire(); //输出 f1 f2

  callbacks = $.Callbacks("memory stopOnFalse");
  callbacks.add(f1);
  callbacks.add(f2);
  callbacks.fire();     //只输出  f1

  callbacks.add(function() {
    console.log("f3");
  }); //不会输出,memory已经失去作用了
  callbacks.fire();     //重新触发,输出f1
        */

        /*
        var callbacks = $.Callbacks("memory");

callbacks.add( fn1 );
callbacks.fire( "1" );

callbacks.add( fn1 );
callbacks.fire( "2" );

callbacks.add( fn1 );
callbacks.fire( "3" );

callbacks.add( fn1 );
callbacks.fire( "4" );
fn1 says: 1
fn1 says: 1
fn1 says: 2
fn1 says: 2
fn1 says: 2
fn1 says: 3 
fn1 says: 3
fn1 says: 3
fn1 says: 3 
fn1 says: 4 
fn1 says: 4
fn1 says: 4 
fn1 says: 4
        */
        self = {
            // Add a callback or a collection of callbacks to the list
            add: function() {// 回调列表中添加一个回调或回调的集合。
                if ( list ) {
                    // First, we save the current length
                    //首先我们存储当前列表长度
                    var start = list.length;
                    (function add( args ) {
                        //这里处理多参数的情况 ( arguments )如cb.add(aaa,bbb)的情况
                        jQuery.each( args, function( _, arg ) {
                            var type = jQuery.type( arg );
                            if ( type === "function" ) {
                                //防止重复添加(去重操作) // 回调不唯一 或 唯一且不存在,则push  
                                //unique参数体现 //当$.Callbacks('unique')时,保证列表里面不会出现重复的回调
                                if ( !options.unique || !self.has( arg ) ) {
                                    list.push( arg );
                                }
                                // 递归检查
                            } else if ( arg && arg.length && type !== "string" ) {//这个是针对数组形式的,例如, cb.add([aaa,bbb],这里aaa和bbb代表的都是函数) //假如传过来的参数为数组或array-like,则继续调用添加,从这里可以看出add的传参可以有add(fn),add([fn1,fn2]),add(fn1,fn2)
                                // Inspect recursively
                                add( arg );
                            }
                        });
                    })( arguments );
                    // Do we need to add the callbacks to the
                    // current firing batch?
                    // 正在执行的回调执行了add操作,则更新firingLength
                     // 如果回调列表中的回调正在执行时,其中的一个回调函数执行了Callbacks.add操作
                    // 上句话可以简称:如果在执行Callbacks.add操作的状态为firing时
                    // 那么需要更新firingLength值
                    if ( firing ) {
                        firingLength = list.length;
                    // With memory, if we're not firing then
                    // we should call right away
                    // 如果options.memory为true,则再次执行fire,且参数相同,fire中的firingIndex为此时的firingStart
                    } else if ( memory ) {
                        //如果options.memory为true,则将memory做为参数,应用最近增加的回调函数
                        firingStart = start;
                        fire( memory );
                    }
                }
                return this;
            },
            // Remove a callback from the list
            // 从函数列表中删除函数(集)
            remove: function() {// 从回调列表中的删除一个回调或回调集合。
                if ( list ) {
                    jQuery.each( arguments, function( _, arg ) {
                        var index;
                        // while循环的意义在于借助于强大的jQuery.inArray删除函数列表中相同的函数引用(没有设置unique的情况)
                        // jQuery.inArray将每次返回查找到的元素的index作为自己的第三个参数继续进行查找,直到函数列表的尽头
                        // splice删除数组元素,修改数组的结构
                        while( ( index = jQuery.inArray( arg, list, index ) ) > -1 ) {
                            // 查找到所对应的索引,则移除索引项
                            list.splice( index, 1 );
                            // Handle firing indexes
                            // 正在执行的回调执行了remvoe操作,则更新firingLength和firingIndex的值
                            // 在函数列表处于firing状态时,最主要的就是维护firingLength和firgingIndex这两个值
             // 保证fire时函数列表中的函数能够被正确执行(fire中的for循环需要这两个值
                            if ( firing ) {
                                if ( index <= firingLength ) {
                                    firingLength--;
                                }
                                if ( index <= firingIndex ) {
                                    firingIndex--;
                                }
                            }
                        }
                    });
                }
                return this;
            },
            // Check if a given callback is in the list.
            // If no argument is given, return whether or not list has callbacks attached.
            // 回调函数是否在列表中.
            has: function( fn ) {//确定列表中是否提供一个回调
                return fn ? jQuery.inArray( fn, list ) > -1 : !!( list && list.length );
            },
            // 从列表中删除所有回调函数
            // Remove all callbacks from the list
            empty: function() {//从列表中删除所有的回调.
                list = [];
                firingLength = 0;
                return this;
            },
            // Have the list do nothing anymore
            // 禁用回调列表中的回调。
            disable: function() {//禁用回调列表中的回调 // 禁用add,remove,fire主要方法的工作
                list = stack = memory = undefined;
                return this;
            },
            // Is it disabled?//  列表中否被禁用
            disabled: function() {//确定回调列表是否已被禁用。
                return !list;
            },
            // Lock the list in its current state// 锁定列表
            lock: function() {//锁定当前状态的回调列表。
                // 如果回调执行过,则将阻止self.fire操作
        // 但如果 options.memory = true,则仍然会执行fire操作
                stack = undefined;
                // 回调未执行,则禁用
                if ( !memory ) {
                    self.disable();
                }
                return this;
            },
            // Is it locked?// 列表是否被锁
            locked: function() {//确定回调列表是否已被锁定。
                return !stack;
            },
            // Call all callbacks with the given context and arguments// 以给定的上下文和参数调用所有回调函数
            fireWith: function( context, args ) {
                // 回调未执行 或 已执行且可以执行多次
                if ( list && ( !fired || stack ) ) {
                    args = args || [];
                    //判断args是不是数组
                    args = [ context, args.slice ? args.slice() : args ];
                    // 正在执行的回调函数执行了fireWith操作( 暗指回调列表已执行过,且可以执行多次,stack = []; )
          // 该函数需要条件执行,或有移除该函数的操作,否则陷入死循环,详见例2
                    if ( firing ) {
                        //如果正在回调
                        //将参数推入堆栈,等待当前回调结束再调用
                        stack.push( args );
                    } else {// 正在执行的回调函数没有执行fireWith操作//否则直接调用
                        //调用内部的fire方法
                        fire( args );
                    }
                }
                return this;
            },
            // Call all the callbacks with the given arguments
            fire: function() {// 用给定的参数调用所有的回调
                self.fireWith( this, arguments );
                return this;
            },
            // To know if the callbacks have already been called at least once
            // 回调函数列表是否至少被调用一次
            fired: function() {//访问给定的上下文和参数列表中的所有回调。
                return !!fired;
            }
        };

    return self;
};
//当我们了解了Deferred后,可用$.ajax('xxx.php').done(function(){alert("成功");}).fail(function(){alert("失败");});
//done和fail对应add;resolve和reject对应fire.相应的进行触发。resolve对应done,reject对应fail
//resolve和reject只会一次触发,而notify可以连续触发
jQuery.extend({
    //Deferred是基于Callbacks开发的,所以真正调用的还是Callbacks
    Deferred: function( func ) {
        //回调方法/事件订阅 done,fail,progress; 通知方法/事件发布 resolve,reject,notify,resolveWith,rejectWith,notifyWith
        //tuples 元素集 其实是把相同有共同特性的代码的给合并成一种结构,然后通过一次处理
        var tuples = [
                // action, add listener, listener list, final state
                //成功 失败 处理中 (这是Callbacks中的fire和add抽象出来对应的3种状态) 
                //resolve/reject/notiy对应状态,done/fail/progress对应回调方法,紧接着的对应回调对象来实现回调方法,最后的是最终完成的状态。
                [ "resolve", "done", jQuery.Callbacks("once memory"), "resolved" ],
                [ "reject", "fail", jQuery.Callbacks("once memory"), "rejected" ],
                [ "notify", "progress", jQuery.Callbacks("memory") ]
            ],
            state = "pending",//等待状态  deferred的状态,分为三种:pending(初始状态), resolved(解决状态), rejected(拒绝状态)
            promise = {
                state: function() {
                    return state;
                },
                //always是总是会触发
                always: function() {
                    deferred.done( arguments ).fail( arguments );
                    return this;
                },
                then: function( /* fnDone, fnFail, fnProgress */ ) {
                    var fns = arguments;
                    //return是针对pipe()方法的,它的使用详见2_8图片所示,创建一个延迟对象进行相应操作,之后可在此基础上再创建一个新的延迟对象并进行相应的操作。就是给人一种继承的感觉
                    return jQuery.Deferred(function( newDefer ) {
                        //对数组tuples进行遍历。
                        jQuery.each( tuples, function( i, tuple ) {
                            var action = tuple[ 0 ],
                            //判断是否为函数,如果是函数就返回该函数fns[ i ],如果不是函数就返回false
                                fn = jQuery.isFunction( fns[ i ] ) && fns[ i ];
                            // deferred[ done | fail | progress ] for forwarding actions to newDefer
                            deferred[ tuple[1] ](function() {
                                //start...
                                var returned = fn && fn.apply( this, arguments );
                                if ( returned && jQuery.isFunction( returned.promise ) ) {
                                    returned.promise()
                                        .done( newDefer.resolve )
                                        .fail( newDefer.reject )
                                        .progress( newDefer.notify );
                                } else {
                                    //这里有return就走return,若无return就走arguments
                                    newDefer[ action + "With" ]( this === promise ? newDefer.promise() : this, fn ? [ returned ] : arguments );
                                }
                                //end...
                                //其实从start...到end...是和then没什么关系的,它主要是和pipe有关系
                            });
                        });
                        fns = null;
                    }).promise();//这里的promise()说明了返回的就是不能够修改状态的延迟对象。
                },
                // Get a promise for this deferred
                // If obj is provided, the promise aspect is added to the object
                promise: function( obj ) {//在有无参数情况下处理是不同的
                    //通过这句话,就把promise的东西全继承给deferred.
                    return obj != null ? jQuery.extend( obj, promise ) : promise;
                }
            },
            deferred = {};

        // Keep pipe for back-compat,兼容了老版本,promise.pipe是以前版本的,而promise.then是后来版本的,后来发现两者可以合并,但是它们实现的功能还是有区别的
        //pipe就是管道的意思,它是说把延迟对象拉的更长一些,可能是为了满足更复杂的需求吧
        //这说明pipe和then是一样的,but 虽然代码一样,但它们各自实现的功能是不一样的。
        //兼容老版本
        promise.pipe = promise.then;

        // Add list-specific methods(对上面的映射数组tuples进行遍历)
        jQuery.each( tuples, function( i, tuple ) {
            var list = tuple[ 2 ],
                stateString = tuple[ 3 ];

            // promise[ done | fail | progress ] = list.add  promise是延迟对象哟,把add方法放入到赋值给promoise。
            promise[ tuple[1] ] = list.add;

            // Handle state
            //这里处理的是if state=resolve,则它就不可能是reject;if state=reject,则它就不可能是resolve;对状态进行了处理
            if ( stateString ) {
                //add是可以进行累加的
                list.add(function() {
                    // state = [ resolved | rejected ]
                    state = stateString;

                // [ reject_list | resolve_list ].disable; progress_list.lock// 位运算。实际上第二个传参数是1、0索引对调了,所以取值是failList.disable与doneList.disable,disable是全部阻止,lock是上锁的操作。
                }, tuples[ i ^ 1 ][ 2 ].disable, tuples[ 2 ][ 2 ].lock );
            }
            /*
            resolve/reject/notify 是 callbacks.fireWith,执行回调函数
      resolveWith/rejectWith/notifyWith 是 callbacks.fireWith 队列方法引用
            */

            // deferred[ resolve | reject | notify ]  deferred也是延迟对象,要注意deferred和promise的区别
            deferred[ tuple[0] ] = function() {
                deferred[ tuple[0] + "With" ]( this === deferred ? promise : this, arguments );
                return this;
            };
            deferred[ tuple[0] + "With" ] = list.fireWith;
        });

        // Make the deferred a promise
        //最后合并promise到deferred
        //所以最终通过工厂方法Deferred构建的异步对象带的所有的方法了
        promise.promise( deferred );

        //注意:promise和deerred都是延迟对象

        // Call given func if any
        if ( func ) {
            func.call( deferred, deferred );
        }

        // All done!
        return deferred;
    },

    // Deferred helper
    //注意用when的时候对应的函数参数应返回延迟对象,如 return dfd.不然的话when会把这个函数作为普通函数(和延迟对象无任何关系)
    //so 总结而言就是:如果when传参but没有返回延迟对象或者没有传参,则when均会自动跳过,认为它们和延迟对象无任何关系。
    //when是辅助Deferred对象的,说白了就是一个帮手
    when: function( subordinate /* , ..., subordinateN */ ) {
        var i = 0,
            resolveValues = core_slice.call( arguments ),
            length = resolveValues.length,

            // the count of uncompleted subordinates 计数器,表示未完成的延迟对象有多少个,从而才能返回all 成功还是其中有失败的。jQuery.isFunction( subordinate.promise )就是判断返回值是否是延迟对象。remaining即为计数器(记录未完成的个数)
            remaining = length !== 1 || ( subordinate && jQuery.isFunction( subordinate.promise ) ) ? length : 0,

            // the master Deferred. If resolveValues consist of only a single Deferred, just use that.
            //deferred即为延迟对象
            deferred = remaining === 1 ? subordinate : jQuery.Deferred(),

            // Update function for both resolve and progress values
            updateFunc = function( i, contexts, values ) {
                return function( value ) {
                    contexts[ i ] = this;
                    values[ i ] = arguments.length > 1 ? core_slice.call( arguments ) : value;
                    if( values === progressValues ) {
                        deferred.notifyWith( contexts, values );
                    } else if ( !( --remaining ) ) {
                        deferred.resolveWith( contexts, values );
                    }
                };
            },

            progressValues, progressContexts, resolveContexts;

        // add listeners to Deferred subordinates; treat others as resolved
        if ( length > 1 ) {
            progressValues = new Array( length );//进行过程中值
            progressContexts = new Array( length );//进行过程中作用域
            resolveContexts = new Array( length );//成功作用域
            for ( ; i < length; i++ ) {
                if ( resolveValues[ i ] && jQuery.isFunction( resolveValues[ i ].promise ) ) {
                    resolveValues[ i ].promise()
                    //resolveValues就是你传的参数的集合
                        .done( updateFunc( i, resolveContexts, resolveValues ) )
                        .fail( deferred.reject )
                        .progress( updateFunc( i, progressContexts, progressValues ) );
                } else {
                    //上面的if已经做了判断是否为延迟对象,如果不是,则对普通函数进行计数器减少
                    --remaining;
                }
            }
        }

        // if we're not waiting on anything, resolve the master触发
        if ( !remaining ) {
            deferred.resolveWith( resolveContexts, resolveValues );
        }
    //返回延迟对象状态
        return deferred.promise();
    }
});
jQuery.support = (function( support ) {
    //采用创建元素的方式对兼容性检测
    var input = document.createElement("input"),
        fragment = document.createDocumentFragment(),
        div = document.createElement("div"),
        select = document.createElement("select"),
        opt = select.appendChild( document.createElement("option") );

    // Finish early in limited environments
    if ( !input.type ) {
        return support;
    }

    input.type = "checkbox";

    // Support: Safari 5.1, iOS 5.1, Android 4.x, Android 2.3
    // Check the default checkbox/radio value ("" on old WebKit; "on" elsewhere)
    support.checkOn = input.value !== "";

    // Must access the parent to make an option select properly
    // Support: IE9, IE10
    support.optSelected = opt.selected;

    // Will be defined later首先定义值,后续再进行处理。之所以这样做是因为这几个值会等待页面全部加载完成后才能真正判断出来,而那些无需赋初始值就直接进行判断的是因为页面一加载就可以判断出来的
    support.reliableMarginRight = true;
    support.boxSizingReliable = true;
    support.pixelPosition = false;

    // Make sure checked status is properly cloned
    // Support: IE9, IE10
    input.checked = true;
    support.noCloneChecked = input.cloneNode( true ).checked;

    // Make sure that the options inside disabled selects aren't marked as disabled
    // (WebKit marks them as disabled)
    select.disabled = true;
    support.optDisabled = !opt.disabled;

    // Check if an input maintains its value after becoming a radio
    // Support: IE9, IE10

    //注意这里顺序书写的问题导致的兼容性问题
    input = document.createElement("input");
    input.value = "t";
    input.type = "radio";
    support.radioValue = input.value === "t";

    // #11217 - WebKit loses check when the name is after the checked attribute
    input.setAttribute( "checked", "t" );
    input.setAttribute( "name", "t" );

    fragment.appendChild( input );

    // Support: Safari 5.1, Android 4.x, Android 2.3
    // old WebKit doesn't clone checked state correctly in fragments
    support.checkClone = fragment.cloneNode( true ).cloneNode( true ).lastChild.checked;

    // Support: Firefox, Chrome, Safari
    // Beware of CSP restrictions (https://developer.mozilla.org/en/Security/CSP)
    //onfocusin是个事件
    support.focusinBubbles = "onfocusin" in window;

    div.style.backgroundClip = "content-box";
    div.cloneNode( true ).style.backgroundClip = "";
    //元素是否会受到克隆的影响
    support.clearCloneStyle = div.style.backgroundClip === "content-box";

    // Run tests that need a body at doc ready
    //等待DOM加载完才进行的功能检测
    jQuery(function() {
        var container, marginDiv,
            // Support: Firefox, Android 2.3 (Prefixed box-sizing versions).
            //box-sizing主要是测试当前页面是标准模式还是怪异模式content-box就是标准模式,border-box是怪异模式
         //标准模式和怪异模式主要是影响了布局中的盒模型
            divReset = "padding:0;margin:0;border:0;display:block;-webkit-box-sizing:content-box;-moz-box-sizing:content-box;box-sizing:content-box",
            body = document.getElementsByTagName("body")[ 0 ];

        if ( !body ) {
            // Return for frameset docs that don't have a body
            return;
        }

        container = document.createElement("div");
        //left:-9999px;是让它不要显示在页面之中,待检测完成后再把它从页面中删除。margin-top:1px是同jQuery 1点几的版本有关的,原因就是jquery2.几的版本相对于1.几的版本功能检测的要少一些
        container.style.cssText = "border:0;width:0;height:0;position:absolute;top:0;left:-9999px;margin-top:1px";

        // Check box-sizing and margin behavior.
        body.appendChild( container ).appendChild( div );
        div.innerHTML = "";
        // Support: Firefox, Android 2.3 (Prefixed box-sizing versions).

        div.style.cssText = "-webkit-box-sizing:border-box;-moz-box-sizing:border-box;box-sizing:border-box;padding:1px;border:1px;display:block;width:4px;margin-top:1%;position:absolute;top:1%";

        // Workaround failing boxSizing test due to offsetWidth returning wrong value
        // with some non-1 values of body zoom, ticket #13543
        //css转换方法,zoom设置页面的显示比例
        jQuery.swap( body, body.style.zoom != null ? { zoom: 1 } : {}, function() {
            support.boxSizing = div.offsetWidth === 4;
        });

        // Use window.getComputedStyle because jsdom on node.js will break without it.
        if ( window.getComputedStyle ) {
            support.pixelPosition = ( window.getComputedStyle( div, null ) || {} ).top !== "1%";
            support.boxSizingReliable = ( window.getComputedStyle( div, null ) || { width: "4px" } ).width === "4px";

            // Support: Android 2.3
            // Check if div with explicit width and no margin-right incorrectly
            // gets computed margin-right based on width of container. (#3333)
            // WebKit Bug 13343 - getComputedStyle returns wrong value for margin-right
            marginDiv = div.appendChild( document.createElement("div") );
            marginDiv.style.cssText = div.style.cssText = divReset;
            marginDiv.style.marginRight = marginDiv.style.width = "0";
            div.style.width = "1px";

            support.reliableMarginRight =
                !parseFloat( ( window.getComputedStyle( marginDiv, null ) || {} ).marginRight );
        }

        body.removeChild( container );
    });

    return support;
})( {} );//传json参数进去,且本函数最终返回json support.

/*
data_user 存储对象
data-priv 存储对象

data_user和data_priv, 就如其名, 一个是用户用的, 一个是jQuery私有的, 他们都是一个叫Data的实例对象
    Implementation Summary

    1. Enforce API surface and semantic compatibility with 1.9.x branch
    2. Improve the module's maintainability by reducing the storage
        paths to a single mechanism.
    3. Use the same single mechanism to support "private" and "user" data.
    4. _Never_ expose "private" data to user code (TODO: Drop _data, _removeData)
    5. Avoid exposing implementation details on user objects (eg. expando properties)
    6. Provide a clear path for implementation upgrade to WeakMap in 2014
*/
var data_user, data_priv, 
    rbrace = /(?:\{[\s\S]*\}|\[[\s\S]*\])$/,
    rmultiDash = /([A-Z])/g;

/*
cache对象结构应该像下面这样:
var cache = {
    "uid1": { // DOM节点1缓存数据,
        "name1": value1,
        "name2": value2
    },
    "uid2": { // DOM节点2缓存数据,
        "name1": value1,
        "name2": value2
    }
    // ......
};
*/

function Data() {
    // Support: Android < 4,
    // Old WebKit does not have Object.preventExtensions/freeze method,
    // return new empty object instead with no [[set]] accessor
    //先在jQuery内部创建一个cache对象{}, 来保存缓存数据。 然后往需要进行缓存的DOM节点上扩展一个值为expando的属性
    //注:expando的值,用于把当前数据缓存的UUID值做一个节点的属性给写入到指定的元素上形成关联桥梁,所以,所以元素本身具有这种属性的可能性很少,所以可以忽略冲突。
    Object.defineProperty( this.cache = {}, 0, {
        get: function() {
            return {};
        }
    });
   //dom与data映射的uuid  // 每个jQuery拷贝都有一个其唯一的标志。比如你的页面有两个iframe且每个iframe都用到的jQuery。name你的两个iframe就有两份jQuery拷贝。
    this.expando = jQuery.expando + Math.random();
}

//接着把每个节点的dom[expando]的值都设为一个自增的变量id,保持全局唯一性。 这个id的值就作为cache的key用来关联DOM节点和数据。也就是说cache[id]就取到了这个节点上的所有缓存,即id就好比是打开一个房间(DOM节点)的钥匙。 而每个元素的所有缓存都被放到了一个map映射里面,这样可以同时缓存多个数据。
//关联起dom对象与数据缓存对象的一个索引标记,换句话说.先在dom元素上找到expando对应值,也就uid,然后通过这个uid找到数据cache对象中的内容
//每个uid对应一个elem缓存数据,每个缓存对象是可以由多个name/value(名值对)对组成的,而value是可以是任何数据类型的。

Data.uid = 1;//每次自增变量

/**
     * 只能接受
     * 元素节点
     * 文档节点
     * 任何对象
     * @param  {[type]} owner [description]
     * @return {[type]}       [description]
     */
/主要用在acceptData函数中确定元素是否可以添加expando属性     
Data.accepts = function( owner ) {
    // Accepts only:
    //  - Node
    //    - Node.ELEMENT_NODE
    //    - Node.DOCUMENT_NODE
    //  - Object
    //    - Any
    return owner.nodeType ?
        owner.nodeType === 1 || owner.nodeType === 9 : true;
};

Data.prototype = {
    // 只能保证是DOM节点才可以
            //  
            //  以前的版本用的 逆天的 valueOf重写保存变量,但是太吃内存了
            //  
    key: function( owner ) {
        //key函数是让DOM元素设置xxx="key值",然后在把往catch里写json(key{})的方式,只不过刚开始json是空的,等调用了set函数后就会相应设置值了 
        // We can accept data for non-element nodes in modern browsers,
        // but we should not, see #8335.
        // Always return the key for a frozen object.
        if ( !Data.accepts( owner ) ) {
            return 0;
        }

        var descriptor = {},
            // Check if the owner object already has a cache key
            // 看看node对象有没有这个UUID映射
            unlock = owner[ this.expando ];

        // If not, create one// 如果没有,就创建它
        if ( !unlock ) {
            unlock = Data.uid++;

            // Secure it in a non-enumerable, non-writable property
            // 为了安全起见,这个值通过es5设置,保证不能遍历,不能改写
            try {
                descriptor[ this.expando ] = { value: unlock };
                Object.defineProperties( owner, descriptor );

            // Support: Android < 4
            // Fallback to a less secure definition
            } catch ( e ) {
                descriptor[ this.expando ] = unlock;
                jQuery.extend( owner, descriptor );
            }
        }

        // Ensure the cache object
        if ( !this.cache[ unlock ] ) {// 确保缓存中有个对象容器
            this.cache[ unlock ] = {};
        }

        return unlock;
    },
    set: function( owner, data, value ) {
        var prop,
            // There may be an unlock assigned to this node,
            // if there is no entry for this "owner", create one inline
            // and set the unlock as though an owner entry had always existed
            // 可能是一个解锁后分配给这个节点
                // 统一创建
            unlock = this.key( owner ),
            cache = this.cache[ unlock ];

        // Handle: [ owner, key, value ] args
        // 根据传递的参数类型,保存到cache上
        if ( typeof data === "string" ) {
            cache[ data ] = value;

        // Handle: [ owner, { properties } ] args
        } else {
            // Fresh assignments by object are shallow copied
            if ( jQuery.isEmptyObject( cache ) ) {
                jQuery.extend( this.cache[ unlock ], data );
            // Otherwise, copy the properties one-by-one to the cache object
            } else {
                for ( prop in data ) {//分解对象
                    cache[ prop ] = data[ prop ];
                }
            }
        }
        return cache;
    },
    get: function( owner, key ) {
        // Either a valid cache is found, or will be created.
        // New caches will be created and the unlock returned,
        // allowing direct access to the newly created
        // empty data object. A valid owner object must be provided.
        // 取出所有的缓存
        var cache = this.cache[ this.key( owner ) ];

        return key === undefined ?//根据key找到对应的数据
            cache : cache[ key ];
    },
    /**
         * 存储器
         * 可以set 与 get处理
         */
    access: function( owner, key, value ) {
        var stored;
        // In cases where either:
        //
        //   1. No key was specified
        //   2. A string key was specified, but no value provided
        //
        // Take the "read" path and allow the get method to determine
        // which value to return, respectively either:
        //
        //   1. The entire cache object
        //   2. The data stored at the key
        //
        if ( key === undefined ||
                ((key && typeof key === "string") && value === undefined) ) {

            stored = this.get( owner, key );

            return stored !== undefined ?
                stored : this.get( owner, jQuery.camelCase(key) );
        }

        // [*]When the key is not a string, or both a key and value
        // are specified, set or extend (existing objects) with either:
        //
        //   1. An object of properties
        //   2. A key and value
        //
        this.set( owner, key, value );

        // Since the "set" path can have two possible entry points
        // return the expected data based on which path was taken[*]
        return value !== undefined ? value : key;
    },
    remove: function( owner, key ) {
        var i, name, camel,
            unlock = this.key( owner ),
            cache = this.cache[ unlock ];

        if ( key === undefined ) {
            this.cache[ unlock ] = {};

        } else {
            // Support array or space separated string of keys
            if ( jQuery.isArray( key ) ) {
                // If "name" is an array of keys...
                // When data is initially created, via ("key", "val") signature,
                // keys will be converted to camelCase.
                // Since there is no way to tell _how_ a key was added, remove
                // both plain key and camelCase key. #12786
                // This will only penalize the array argument path.
                name = key.concat( key.map( jQuery.camelCase ) );
            } else {
                camel = jQuery.camelCase( key );
                // Try the string as a key before any manipulation
                if ( key in cache ) {
                    name = [ key, camel ];
                } else {
                    // If a key with the spaces exists, use it.
                    // Otherwise, create an array by matching non-whitespace
                    name = camel;
                    name = name in cache ?
                        [ name ] : ( name.match( core_rnotwhite ) || [] );
                }
            }

            i = name.length;
            while ( i-- ) {
                delete cache[ name[ i ] ];
            }
        }
    },
    hasData: function( owner ) {
        return !jQuery.isEmptyObject(
            this.cache[ owner[ this.expando ] ] || {}
        );
    },
    discard: function( owner ) {
        if ( owner[ this.expando ] ) {
            delete this.cache[ owner[ this.expando ] ];
        }
    }
};

// These may be used throughout the jQuery core codebase
data_user = new Data();//存数据的//用户使用
  //存储对象
    //jQuery内部私有
    //用来存事件的, 如click事件那种  
data_priv = new Data();


jQuery.extend({
    //可接受数据的范围
    acceptData: Data.accepts,
/**
         * 是否有数据
         * @param  {[type]} elem [description]
         * @return {[type]}      [description]
         */
    hasData: function( elem ) {
        return data_user.hasData( elem ) || data_priv.hasData( elem );
    },

    data: function( elem, name, data ) {
        return data_user.access( elem, name, data );
    },

    removeData: function( elem, name ) {
        data_user.remove( elem, name );
    },

    // TODO: Now that all calls to _data and _removeData have been replaced
    // with direct calls to data_priv methods, these can be deprecated.
    // 内部使用
    _data: function( elem, name, data ) {
        return data_priv.access( elem, name, data );
    },

    _removeData: function( elem, name ) {
        data_priv.remove( elem, name );
    }
});

jQuery.fn.extend({
    data: function( key, value ) {//内部使用基础api:jQuery.data来实现,可以使用参数(key,value),也可以使用参数(obj)
        var attrs, name,
            elem = this[ 0 ],
            i = 0,
            data = null;

        // Gets all values
        if ( key === undefined ) {
            if ( this.length ) {
                data = data_user.get( elem );

                if ( elem.nodeType === 1 && !data_priv.get( elem, "hasDataAttrs" ) ) {
                    attrs = elem.attributes;
                    for ( ; i < attrs.length; i++ ) {
                        name = attrs[ i ].name;

                        if ( name.indexOf( "data-" ) === 0 ) {
                            name = jQuery.camelCase( name.slice(5) );
                            dataAttr( elem, name, data[ name ] );
                        }
                    }
                    data_priv.set( elem, "hasDataAttrs", true );
                }
            }

            return data;
        }

        // Sets multiple values
        if ( typeof key === "object" ) {
            return this.each(function() {
                data_user.set( this, key );
            });
        }

        return jQuery.access( this, function( value ) {
            var data,
                camelKey = jQuery.camelCase( key );

            // The calling jQuery object (element matches) is not empty
            // (and therefore has an element appears at this[ 0 ]) and the
            // `value` parameter was not undefined. An empty jQuery object
            // will result in `undefined` for elem = this[ 0 ] which will
            // throw an exception if an attempt to read a data cache is made.
            if ( elem && value === undefined ) {
                // Attempt to get data from the cache
                // with the key as-is
                data = data_user.get( elem, key );
                if ( data !== undefined ) {
                    return data;
                }

                // Attempt to get data from the cache
                // with the key camelized
                data = data_user.get( elem, camelKey );
                if ( data !== undefined ) {
                    return data;
                }

                // Attempt to "discover" the data in
                // HTML5 custom data-* attrs
                data = dataAttr( elem, camelKey, undefined );
                if ( data !== undefined ) {
                    return data;
                }

                // We tried really hard, but the data doesn't exist.
                return;
            }

            // Set the data...
            this.each(function() {
                // First, attempt to store a copy or reference of any
                // data that might've been store with a camelCased key.
                var data = data_user.get( this, camelKey );

                // For HTML5 data-* attribute interop, we have to
                // store property names with dashes in a camelCase form.
                // This might not apply to all properties...*
                data_user.set( this, camelKey, value );

                // *... In the case of properties that might _actually_
                // have dashes, we need to also store a copy of that
                // unchanged property.
                if ( key.indexOf("-") !== -1 && data !== undefined ) {
                    data_user.set( this, key, value );
                }
            });
        }, null, value, arguments.length > 1, null, true );
    },

    removeData: function( key ) {//内部使用基础api: jQuery.removeData来实现
        return this.each(function() {
            data_user.remove( this, key );
        });
    }
});

/**
     * 处理HTML5的data-*属性
     * 逻辑结构更为清晰
     * @param  {[type]} elem [description]
     * @param  {[type]} key  [description]
     * @param  {[type]} data [description]
     * @return {[type]}      [description]
     */
function dataAttr( elem, key, data ) {
    var name;

    // If nothing was found internally, try to fetch any
    // data from the HTML5 data-* attribute
    if ( data === undefined && elem.nodeType === 1 ) {
        name = "data-" + key.replace( rmultiDash, "-$1" ).toLowerCase();
        data = elem.getAttribute( name );

        if ( typeof data === "string" ) {
            try {
                data = data === "true" ? true :
                    data === "false" ? false :
                    data === "null" ? null :
                    // Only convert to a number if it doesn't change the string
                    +data + "" === data ? +data :
                    rbrace.test( data ) ? JSON.parse( data ) :
                    data;
            } catch( e ) {}

            // Make sure we set the data so it isn't changed later
            data_user.set( elem, key, data );
        } else {
            data = undefined;
        }
    }
    return data;
}

/**
 * jQuery队列
 * jQuery的队列依赖缓存机制事件,它同时是animate的基础。
 * 它不像事件机制、缓存机制、回调机制一样有自己的命名空间,
 * 由于比较简单,所以直接挂在到$和jQuery对象上。
 */
jQuery.extend({
    //加入动画队列
    //将data按照某种类型存储到elem对应的队列中,并等待执行。同时返回目前队列中的所有数据
    第一个参数elem是DOM元素,第二个参数type是字符串,第三个参数data可以是function或数组。
    queue: function( elem, type, data ) {
        var queue;

        if ( elem ) {
            //默认处理动画队列 默认队列的名称是fx
            type = ( type || "fx" ) + "queue";
            //取出关联到现有元素上的所有队列
            queue = data_priv.get( elem, type );

            // Speed up dequeue by getting out quickly if this is just a lookup
            if ( data ) {
                //如果elem还没有在cache中存储过名为type的数据,或者需要存储的数据时数组
                if ( !queue || jQuery.isArray( data ) ) {
                    queue = data_priv.access( elem, type, jQuery.makeArray(data) );
                } else {
                    queue.push( data );
                }
            }
            return queue || [];
        }
    },
   //执行动画队列
    //出列操作,如果想要执行队列中的所有方法,则有多少个方法就需要执行多少次dequeue方法
    dequeue: function( elem, type ) {
        //如果指定类型就按照指定类型查找,否则默认是“fx”
        type = type || "fx";

        var queue = jQuery.queue( elem, type ),
            startLength = queue.length,
            //取出队列(数组)中的第一个值(先进先出),
            //第一个数据是上一次执行dequeue时添加到队列中的“inprogress”占位符
            fn = queue.shift(),
            hooks = jQuery._queueHooks( elem, type ),
            //预先准备好下一个队列操作
            next = function() {
                jQuery.dequeue( elem, type );
            };

        // If the fx queue is dequeued, always remove the progress sentinel
        // 当进行出栈操作时,总是删除名为“inprogress”的数据,并继续取下一条。
        // 队列中也存在占位符,用于动画处理
        if ( fn === "inprogress" ) {
            // 函数执行前, 在queue数组的最前面添加一个进程锁,就实在之前清除的 
            fn = queue.shift();
            startLength--;
        }

        if ( fn ) {

            // Add a progress sentinel to prevent the fx queue from being
            // automatically dequeued
            if ( type === "fx" ) {
                queue.unshift( "inprogress" );
            }

            // clear up the last queue stop function
            delete hooks.stop;
            //执行动画回调
            fn.call( elem, next, hooks );
        }

        if ( !startLength && hooks ) {
            hooks.empty.fire();
        }
    },

    // not intended for public consumption - generates a queueHooks object, or returns the current one
    // 从elem相应类型对应的队列中下一条数据并执行这条数据

    //dequeue不仅是取出来还需要执行,在执行的时候把next与hooks传递给外部的回调
    //这就是js的逻辑上的很绕的地方,在内部可以传递一个引用出去,又能提供外部调用或者执行
    _queueHooks: function( elem, type ) {
        var key = type + "queueHooks";
        return data_priv.get( elem, key ) || data_priv.access( elem, key, {
            empty: jQuery.Callbacks("once memory").add(function() {
                data_priv.remove( elem, [ type + "queue", key ] );
            })
        });
    }
});
//内部动画队列
jQuery.fn.extend({
    //queue方法,相当于数组中的push操作。dequeue相当于数组的shift操作。
    queue: function( type, data ) {
        var setter = 2;
    //修正type, 默认为表示jquery动画的fx, 如果不为"fx", 
        //即为自己的自定义动画, 一般我们用"fx"就足够了.
        if ( typeof type !== "string" ) {
            data = type;
            type = "fx";
            setter--;
        }
    //只有动画的回调
        if ( arguments.length < setter ) {
            return jQuery.queue( this[0], type );
        }
    //生成的动画数据
        //动画队列
        //动画钩子
        return data === undefined ?
            this :
            this.each(function() {
                //调用基础队列
                //设置动画队列缓存
                //并返回队列总数
                var queue = jQuery.queue( this, type, data );

                // ensure a hooks for this queue
                // 确保是一个队列钩子
                jQuery._queueHooks( this, type );
                //直接执行动画队列
                //防止在执行函数的时候, 这里又进行dequeue操作, 这样会同时执行2个函数, 队列就不受控制了.
                //其实就是通过inprogress这个参数。判断从什么时候开始真正执行动画

                if ( type === "fx" && queue[0] !== "inprogress" ) {
                    //如果队列没有被锁住, 即此时没有在执行dequeue. 移出队列里第一个函数并执行它.
                    jQuery.dequeue( this, type );
                }
            });
    },
    dequeue: function( type ) {
        return this.each(function() {
            jQuery.dequeue( this, type );
        });
    },
    // Based off of the plugin by Clint Helfers, with permission.
    // http://blindsignals.com/index.php/2009/07/jquery-delay/
    delay: function( time, type ) {
        time = jQuery.fx ? jQuery.fx.speeds[ time ] || time : time;
        type = type || "fx";

        return this.queue( type, function( next, hooks ) {
            var timeout = setTimeout( next, time );
            hooks.stop = function() {
                clearTimeout( timeout );
            };
        });
    },
    clearQueue: function( type ) {
        return this.queue( type || "fx", [] );
    },
    // Get a promise resolved when queues of a certain type
    // are emptied (fx is the type by default)
    promise: function( type, obj ) {
        var tmp,
            count = 1,
            defer = jQuery.Deferred(),
            elements = this,
            i = this.length,
            resolve = function() {
                if ( !( --count ) ) {
                    defer.resolveWith( elements, [ elements ] );
                }
            };

        if ( typeof type !== "string" ) {
            obj = type;
            type = undefined;
        }
        type = type || "fx";

        while( i-- ) {
            tmp = data_priv.get( elements[ i ], type + "queueHooks" );
            if ( tmp && tmp.empty ) {
                count++;
                tmp.empty.add( resolve );
            }
        }
        resolve();
        return defer.promise( obj );
    }
});
var nodeHook, boolHook,
    rclass = /[\t\r\n\f]/g,
    rreturn = /\r/g,
    rfocusable = /^(?:input|select|textarea|button)$/i;

//这里的jQuery.fn.extend是用于外部使用的,也就是这里的方法调用了jQuery.extend中的方法。
jQuery.fn.extend({
    attr: function( name, value ) {
        return jQuery.access( this, jQuery.attr, name, value, arguments.length > 1 );
    },

    removeAttr: function( name ) {
        return this.each(function() {
            jQuery.removeAttr( this, name );
        });
    },

    prop: function( name, value ) {
        return jQuery.access( this, jQuery.prop, name, value, arguments.length > 1 );
    },

    removeProp: function( name ) {
        return this.each(function() {
            delete this[ jQuery.propFix[ name ] || name ];
        });
    },

    addClass: function( value ) {
        var classes, elem, cur, clazz, j,
            i = 0,
            len = this.length,
            proceed = typeof value === "string" && value;

        if ( jQuery.isFunction( value ) ) {
            return this.each(function( j ) {
                jQuery( this ).addClass( value.call( this, j, this.className ) );
            });
        }

        if ( proceed ) {
            // The disjunction here is for better compressibility (see removeClass)
            classes = ( value || "" ).match( core_rnotwhite ) || [];

            for ( ; i < len; i++ ) {
                elem = this[ i ];
                cur = elem.nodeType === 1 && ( elem.className ?
                    ( " " + elem.className + " " ).replace( rclass, " " ) :
                    " "
                );

                if ( cur ) {
                    j = 0;
                    while ( (clazz = classes[j++]) ) {
                        if ( cur.indexOf( " " + clazz + " " ) < 0 ) {
                            cur += clazz + " ";
                        }
                    }
                    elem.className = jQuery.trim( cur );

                }
            }
        }

        return this;
    },

    removeClass: function( value ) {
        var classes, elem, cur, clazz, j,
            i = 0,
            len = this.length,
            proceed = arguments.length === 0 || typeof value === "string" && value;

        if ( jQuery.isFunction( value ) ) {
            return this.each(function( j ) {
                jQuery( this ).removeClass( value.call( this, j, this.className ) );
            });
        }
        if ( proceed ) {
            classes = ( value || "" ).match( core_rnotwhite ) || [];

            for ( ; i < len; i++ ) {
                elem = this[ i ];
                // This expression is here for better compressibility (see addClass)
                cur = elem.nodeType === 1 && ( elem.className ?
                    ( " " + elem.className + " " ).replace( rclass, " " ) :
                    ""
                );

                if ( cur ) {
                    j = 0;
                    while ( (clazz = classes[j++]) ) {
                        // Remove *all* instances
                        while ( cur.indexOf( " " + clazz + " " ) >= 0 ) {
                            cur = cur.replace( " " + clazz + " ", " " );
                        }
                    }
                    elem.className = value ? jQuery.trim( cur ) : "";
                }
            }
        }

        return this;
    },

    toggleClass: function( value, stateVal ) {
        var type = typeof value;

        if ( typeof stateVal === "boolean" && type === "string" ) {
            return stateVal ? this.addClass( value ) : this.removeClass( value );
        }

        if ( jQuery.isFunction( value ) ) {
            return this.each(function( i ) {
                jQuery( this ).toggleClass( value.call(this, i, this.className, stateVal), stateVal );
            });
        }

        return this.each(function() {
            if ( type === "string" ) {
                // toggle individual class names
                var className,
                    i = 0,
                    self = jQuery( this ),
                    classNames = value.match( core_rnotwhite ) || [];

                while ( (className = classNames[ i++ ]) ) {
                    // check each className given, space separated list
                    if ( self.hasClass( className ) ) {
                        self.removeClass( className );
                    } else {
                        self.addClass( className );
                    }
                }

            // Toggle whole class name
            } else if ( type === core_strundefined || type === "boolean" ) {
                if ( this.className ) {
                    // store className if set
                    data_priv.set( this, "__className__", this.className );
                }

                // If the element has a class name or if we're passed "false",
                // then remove the whole classname (if there was one, the above saved it).
                // Otherwise bring back whatever was previously saved (if anything),
                // falling back to the empty string if nothing was stored.
                this.className = this.className || value === false ? "" : data_priv.get( this, "__className__" ) || "";
            }
        });
    },

    hasClass: function( selector ) {
        var className = " " + selector + " ",
            i = 0,
            l = this.length;
        for ( ; i < l; i++ ) {
            if ( this[i].nodeType === 1 && (" " + this[i].className + " ").replace(rclass, " ").indexOf( className ) >= 0 ) {
                return true;
            }
        }

        return false;
    },

    val: function( value ) {
        var hooks, ret, isFunction,
            elem = this[0];

        if ( !arguments.length ) {
            if ( elem ) {
                hooks = jQuery.valHooks[ elem.type ] || jQuery.valHooks[ elem.nodeName.toLowerCase() ];

                if ( hooks && "get" in hooks && (ret = hooks.get( elem, "value" )) !== undefined ) {
                    return ret;
                }

                ret = elem.value;

                return typeof ret === "string" ?
                    // handle most common string cases
                    ret.replace(rreturn, "") :
                    // handle cases where value is null/undef or number
                    ret == null ? "" : ret;
            }

            return;
        }

        isFunction = jQuery.isFunction( value );

        return this.each(function( i ) {
            var val;

            if ( this.nodeType !== 1 ) {
                return;
            }

            if ( isFunction ) {
                val = value.call( this, i, jQuery( this ).val() );
            } else {
                val = value;
            }

            // Treat null/undefined as ""; convert numbers to string
            if ( val == null ) {
                val = "";
            } else if ( typeof val === "number" ) {
                val += "";
            } else if ( jQuery.isArray( val ) ) {
                val = jQuery.map(val, function ( value ) {
                    return value == null ? "" : value + "";
                });
            }

            hooks = jQuery.valHooks[ this.type ] || jQuery.valHooks[ this.nodeName.toLowerCase() ];

            // If set returns undefined, fall back to normal setting
            if ( !hooks || !("set" in hooks) || hooks.set( this, val, "value" ) === undefined ) {
                this.value = val;
            }
        });
    }
});


//这里的jQuery.extend主要是用于内部使用的
jQuery.extend({
    valHooks: {
        option: {
            get: function( elem ) {
                // attributes.value is undefined in Blackberry 4.7 but
                // uses .value. See #6932
                var val = elem.attributes.value;
                return !val || val.specified ? elem.value : elem.text;
            }
        },
        select: {
            get: function( elem ) {
                var value, option,
                    options = elem.options,
                    index = elem.selectedIndex,
                    one = elem.type === "select-one" || index < 0,
                    values = one ? null : [],
                    max = one ? index + 1 : options.length,
                    i = index < 0 ?
                        max :
                        one ? index : 0;

                // Loop through all the selected options
                for ( ; i < max; i++ ) {
                    option = options[ i ];

                    // IE6-9 doesn't update selected after form reset (#2551)
                    if ( ( option.selected || i === index ) &&
                            // Don't return options that are disabled or in a disabled optgroup
                            ( jQuery.support.optDisabled ? !option.disabled : option.getAttribute("disabled") === null ) &&
                            ( !option.parentNode.disabled || !jQuery.nodeName( option.parentNode, "optgroup" ) ) ) {

                        // Get the specific value for the option
                        value = jQuery( option ).val();

                        // We don't need an array for one selects
                        if ( one ) {
                            return value;
                        }

                        // Multi-Selects return an array
                        values.push( value );
                    }
                }

                return values;
            },

            set: function( elem, value ) {
                var optionSet, option,
                    options = elem.options,
                    values = jQuery.makeArray( value ),
                    i = options.length;

                while ( i-- ) {
                    option = options[ i ];
                    if ( (option.selected = jQuery.inArray( jQuery(option).val(), values ) >= 0) ) {
                        optionSet = true;
                    }
                }

                // force browsers to behave consistently when non-matching value is set
                if ( !optionSet ) {
                    elem.selectedIndex = -1;
                }
                return values;
            }
        }
    },

    attr: function( elem, name, value ) {
        var hooks, ret,
            nType = elem.nodeType;

        // don't get/set attributes on text, comment and attribute nodes
        if ( !elem || nType === 3 || nType === 8 || nType === 2 ) {
            return;
        }

        // Fallback to prop when attributes are not supported
        if ( typeof elem.getAttribute === core_strundefined ) {
            return jQuery.prop( elem, name, value );
        }

        // All attributes are lowercase
        // Grab necessary hook if one is defined  jQuery.isXMLDoc调用了Sizzle的isXML方法
        if ( nType !== 1 || !jQuery.isXMLDoc( elem ) ) {
            name = name.toLowerCase();
            hooks = jQuery.attrHooks[ name ] ||
                ( jQuery.expr.match.bool.test( name ) ? boolHook : nodeHook );
        }

        if ( value !== undefined ) {

            if ( value === null ) {
                jQuery.removeAttr( elem, name );

            } else if ( hooks && "set" in hooks && (ret = hooks.set( elem, value, name )) !== undefined ) {
                return ret;

            } else {
                elem.setAttribute( name, value + "" );
                return value;
            }

        } else if ( hooks && "get" in hooks && (ret = hooks.get( elem, name )) !== null ) {
            return ret;

        } else {
            ret = jQuery.find.attr( elem, name );

            // Non-existent attributes return null, we normalize to undefined
            return ret == null ?
                undefined :
                ret;
        }
    },

    removeAttr: function( elem, value ) {
        var name, propName,
            i = 0,
            attrNames = value && value.match( core_rnotwhite );

        if ( attrNames && elem.nodeType === 1 ) {
            while ( (name = attrNames[i++]) ) {
                propName = jQuery.propFix[ name ] || name;

                // Boolean attributes get special treatment (#10870)
                if ( jQuery.expr.match.bool.test( name ) ) {
                    // Set corresponding property to false
                    elem[ propName ] = false;
                }

                elem.removeAttribute( name );
            }
        }
    },

    attrHooks: {
        type: {
            set: function( elem, value ) {
                if ( !jQuery.support.radioValue && value === "radio" && jQuery.nodeName(elem, "input") ) {
                    // Setting the type on a radio button after the value resets the value in IE6-9
                    // Reset value to default in case type is set after value during creation
                    var val = elem.value;
                    elem.setAttribute( "type", value );
                    if ( val ) {
                        elem.value = val;
                    }
                    return value;
                }
            }
        }
    },


/*
由于class属于JavaScript保留值,因此当我们要操作元素的class属性值时,直接使用obj.getAttribute('class')和obj.setAttribute('class', 'value')可能会遭遇浏览器兼容性问题,W3C DOM标准为每个节点提供了一个可读写的className属性,作为节点class属性的映射,标准浏览器的都提供了这一属性的支持,因此,可以使用e.className访问元素的class属性值,也可对该属性进行重新斌值。而IE和Opera中也可使用e.getAttribute('className')和e.setAttribute('className', 'value')访问及修改class属性值。相比之下,e.className是W3C DOM标准,仍然是兼容性最强的解决办法。
同理htmlFor用于读取label标签的for属性
*/
    propFix: {
        "for": "htmlFor",
        "class": "className"
    },

    prop: function( elem, name, value ) {
        var ret, hooks, notxml,
            nType = elem.nodeType;

        // don't get/set properties on text, comment and attribute nodes
        if ( !elem || nType === 3 || nType === 8 || nType === 2 ) {
            return;
        }

        notxml = nType !== 1 || !jQuery.isXMLDoc( elem );

        if ( notxml ) {
            // Fix name and attach hooks
            name = jQuery.propFix[ name ] || name;
            //这里主要是对tabindex做的兼容
            hooks = jQuery.propHooks[ name ];
        }

        if ( value !== undefined ) {
            return hooks && "set" in hooks && (ret = hooks.set( elem, value, name )) !== undefined ?
                ret :
                ( elem[ name ] = value );

        } else {
            return hooks && "get" in hooks && (ret = hooks.get( elem, name )) !== null ?
                ret :
                elem[ name ];
        }
    },

    propHooks: {
        tabIndex: {
            get: function( elem ) {
                return elem.hasAttribute( "tabindex" ) || rfocusable.test( elem.nodeName ) || elem.href ?
                    elem.tabIndex :
                    -1;
            }
        }
    }
});

// Hooks for boolean attributes
/*
属性操作的钩子

propFix

propHooks

attrHooks

valHooks
*/

boolHook = {
    set: function( elem, value, name ) {
        if ( value === false ) {
            // Remove boolean attributes when set to false
            jQuery.removeAttr( elem, name );
        } else {
            elem.setAttribute( name, name );
        }
        return name;
    }
};
jQuery.each( jQuery.expr.match.bool.source.match( /\w+/g ), function( i, name ) {
    var getter = jQuery.expr.attrHandle[ name ] || jQuery.find.attr;

    jQuery.expr.attrHandle[ name ] = function( elem, name, isXML ) {
        var fn = jQuery.expr.attrHandle[ name ],
            ret = isXML ?
                undefined :
                /* jshint eqeqeq: false */
                // Temporarily disable this handler to check existence
                (jQuery.expr.attrHandle[ name ] = undefined) !=
                    getter( elem, name, isXML ) ?

                    name.toLowerCase() :
                    null;

        // Restore handler
        jQuery.expr.attrHandle[ name ] = fn;

        return ret;
    };
});

// Support: IE9+
// Selectedness for an option in an optgroup can be inaccurate   option下的选择框兼容情况
if ( !jQuery.support.optSelected ) {
    jQuery.propHooks.selected = {
        get: function( elem ) {
            var parent = elem.parentNode;
            if ( parent && parent.parentNode ) {
                parent.parentNode.selectedIndex;
            }
            return null;
        }
    };
}

/*
tabIndex 属性可设置或返回按钮的 tab 键控制次序
readonly 属性规定输入字段为只读。
maxlength 属性规定输入字段的最大长度,以字符个数计。
cellspacing 属性规定单元格之间的空间
cellpadding 属性规定单元边沿与其内容之间的空白。
rowspan 属性规定单元格可横跨的行数。
colspan 属性规定单元格可横跨的列数。
HTML <img> 标签的
usemap 属性将图像定义为客户端图像映射
frameBorder 属性设置或返回是否显示框架周围的边框。
contenteditable 属性规定是否可编辑元素的内容。
*/
jQuery.each([
    "tabIndex",
    "readOnly",
    "maxLength",
    "cellSpacing",
    "cellPadding",
    "rowSpan",
    "colSpan",
    "useMap",
    "frameBorder",
    "contentEditable"
], function() {
    //值得一提的是这个方法用的比较巧妙了,收集所有的合集名,然后在每一个上下文回调中把每一个名字传递到propFix方法,key转成小写,value保存正确写法
    jQuery.propFix[ this.toLowerCase() ] = this;
});

// Radios and checkboxes getter/setter
jQuery.each([ "radio", "checkbox" ], function() {
    jQuery.valHooks[ this ] = {
        set: function( elem, value ) {
            if ( jQuery.isArray( value ) ) {
                return ( elem.checked = jQuery.inArray( jQuery(elem).val(), value ) >= 0 );
            }
        }
    };
    if ( !jQuery.support.checkOn ) {
        jQuery.valHooks[ this ].get = function( elem ) {
            // Support: Webkit
            // "" is returned instead of "on" if a value isn't specified
            return elem.getAttribute("value") === null ? "on" : elem.value;
        };
    }
});
var rkeyEvent = /^key/,
    rmouseEvent = /^(?:mouse|contextmenu)|click/,
    rfocusMorph = /^(?:focusinfocus|focusoutblur)$/,
    rtypenamespace = /^([^.]*)(?:\.(.+)|)$/;

function returnTrue() {
    return true;
}

function returnFalse() {
    return false;
}

function safeActiveElement() {
    try {
        return document.activeElement;
    } catch ( err ) { }
}

/*
 * Helper functions for managing events -- not part of the public interface.
 * Props to Dean Edwards' addEvent library for many of the ideas.
 */
 /*
 不管你用的是(click / bind / delegate)之中那个方法,最终都是jQuery底层都是调用on方法来完成最终的事件绑定。
 .on()方法事件处理程序到当前选定的jQuery对象中的元素。在jQuery 1.7中,.on()方法 提供绑定事件处理的所有功能
 */

jQuery.event = {

    global: {},

    add: function( elem, types, handler, data, selector ) {

        var handleObjIn, eventHandle, tmp,
            events, t, handleObj,
            special, handlers, type, namespaces, origType,
            //获取数据缓存,在$.cahce缓存中获取存储的事件句柄对象,如果没就新建elemData
            elemData = data_priv.get( elem );

        // Don't attach events to noData or text/comment nodes (but allow plain objects)
        if ( !elemData ) {
            return;
        }

        // Caller can pass in an object of custom data in lieu of the handler
        if ( handler.handler ) {
            handleObjIn = handler;
            handler = handleObjIn.handler;
            selector = handleObjIn.selector;
        }

        // Make sure that the handler has a unique ID, used to find/remove it later
        if ( !handler.guid ) {
            //为每一个事件的句柄给一个标示,添加ID的目的是 用来寻找或者删除handler,因为这个东东是缓存在缓存对象上的,没有直接跟元素节点发生关联
            handler.guid = jQuery.guid++;
        }

        // Init the element's event structure and main handler, if this is the first
        if ( !(events = elemData.events) ) {
            events = elemData.events = {};
        }
        if ( !(eventHandle = elemData.handle) ) {
            eventHandle = elemData.handle = function( e ) {
                // Discard the second event of a jQuery.event.trigger() and
                // when an event is called after a page has unloaded
                return typeof jQuery !== core_strundefined && (!e || jQuery.event.triggered !== e.type) ?
                    jQuery.event.dispatch.apply( eventHandle.elem, arguments ) :
                    undefined;
            };
            // Add elem as a property of the handle fn to prevent a memory leak with IE non-native events
            eventHandle.elem = elem;
        }

        // Handle multiple events separated by a space// 事件可能是通过空格键分隔的字符串,所以将其变成字符串数组
        types = ( types || "" ).match( core_rnotwhite ) || [""];
        // 例如:'.a .b .c'.match(/\S+/g) → [".a", ".b", ".c"]
    // 事件的个数
        t = types.length;
        while ( t-- ) {
            // 尝试取出事件的命名空间
    // 如"mouseover.a.b" → ["mouseover.a.b", "mouseover", "a.b"]
            tmp = rtypenamespace.exec( types[t] ) || [];
            // 取出事件类型,如mouseover
            type = origType = tmp[1];
            // 取出事件命名空间,如a.b,并根据"."分隔成数组
            namespaces = ( tmp[2] || "" ).split( "." ).sort();

            // There *must* be a type, no attaching namespace-only handlers
            if ( !type ) {
                continue;
            }

            // If event changes its type, use the special event handlers for the changed type
            // 事件是否会改变当前状态,如果会则使用特殊事件
            special = jQuery.event.special[ type ] || {};

            // If selector defined, determine special event api type, otherwise given type
            // 根据是否已定义selector,决定使用哪个特殊事件api,如果没有非特殊事件,则用type
            type = ( selector ? special.delegateType : special.bindType ) || type;

            // Update special based on newly reset type
            // type状态发生改变,重新定义特殊事件
            special = jQuery.event.special[ type ] || {};

            // handleObj is passed to all event handlers
             // 这里把handleObj叫做事件处理对象,扩展一些来着handleObjIn的属性
            handleObj = jQuery.extend({
                type: type,
                origType: origType,
                data: data,
                handler: handler,
                guid: handler.guid,
                selector: selector,
                needsContext: selector && jQuery.expr.match.needsContext.test( selector ),
                namespace: namespaces.join(".")
            }, handleObjIn );

            // Init the event handler queue if we're the first
             // 初始化事件处理列队,如果是第一次使用,将执行语句
            if ( !(handlers = events[ type ]) ) {
                handlers = events[ type ] = [];
                handlers.delegateCount = 0;

                // Only use addEventListener if the special events handler returns false
                // 如果获取特殊事件监听方法失败,则使用addEventListener进行添加事件
                if ( !special.setup || special.setup.call( elem, data, namespaces, eventHandle ) === false ) {
                    if ( elem.addEventListener ) {
                        elem.addEventListener( type, eventHandle, false );
                    }
                }
            }
      // 特殊事件使用add处理
            if ( special.add ) {
                special.add.call( elem, handleObj );
        // 设置事件处理函数的ID
                if ( !handleObj.handler.guid ) {
                    handleObj.handler.guid = handler.guid;
                }
            }

            // Add to the element's handler list, delegates in front
            // 将事件处理对象推入处理列表,姑且定义为事件处理对象包
            if ( selector ) {
                handlers.splice( handlers.delegateCount++, 0, handleObj );
            } else {
                handlers.push( handleObj );
            }

            // Keep track of which events have ever been used, for event optimization
            // 表示事件曾经使用过,用于事件优化
            jQuery.event.global[ type ] = true;
        }

        // Nullify elem to prevent memory leaks in IE
        // 设置为null避免IE中循环引用导致的内存泄露
        elem = null;
    },

    // Detach an event or set of events from an element
    remove: function( elem, types, handler, selector, mappedTypes ) {

        var j, origCount, tmp,
            events, t, handleObj,
            special, handlers, type, namespaces, origType,
            elemData = data_priv.hasData( elem ) && data_priv.get( elem );

        if ( !elemData || !(events = elemData.events) ) {
            return;
        }

        // Once for each type.namespace in types; type may be omitted
        types = ( types || "" ).match( core_rnotwhite ) || [""];
        t = types.length;
        while ( t-- ) {
            tmp = rtypenamespace.exec( types[t] ) || [];
            type = origType = tmp[1];
            namespaces = ( tmp[2] || "" ).split( "." ).sort();

            // Unbind all events (on this namespace, if provided) for the element
            if ( !type ) {
                for ( type in events ) {
                    jQuery.event.remove( elem, type + types[ t ], handler, selector, true );
                }
                continue;
            }

            special = jQuery.event.special[ type ] || {};
            type = ( selector ? special.delegateType : special.bindType ) || type;
            handlers = events[ type ] || [];
            tmp = tmp[2] && new RegExp( "(^|\\.)" + namespaces.join("\\.(?:.*\\.|)") + "(\\.|$)" );

            // Remove matching events
            origCount = j = handlers.length;
            while ( j-- ) {
                handleObj = handlers[ j ];

                if ( ( mappedTypes || origType === handleObj.origType ) &&
                    ( !handler || handler.guid === handleObj.guid ) &&
                    ( !tmp || tmp.test( handleObj.namespace ) ) &&
                    ( !selector || selector === handleObj.selector || selector === "**" && handleObj.selector ) ) {
                    handlers.splice( j, 1 );

                    if ( handleObj.selector ) {
                        handlers.delegateCount--;
                    }
                    if ( special.remove ) {
                        special.remove.call( elem, handleObj );
                    }
                }
            }

            // Remove generic event handler if we removed something and no more handlers exist
            // (avoids potential for endless recursion during removal of special event handlers)
            if ( origCount && !handlers.length ) {
                if ( !special.teardown || special.teardown.call( elem, namespaces, elemData.handle ) === false ) {
                    jQuery.removeEvent( elem, type, elemData.handle );
                }

                delete events[ type ];
            }
        }

        // Remove the expando if it's no longer used
        if ( jQuery.isEmptyObject( events ) ) {
            delete elemData.handle;
            data_priv.remove( elem, "events" );
        }
    },

    trigger: function( event, data, elem, onlyHandlers ) {

        var i, cur, tmp, bubbleType, ontype, handle, special,
            eventPath = [ elem || document ],
            type = core_hasOwn.call( event, "type" ) ? event.type : event,
            namespaces = core_hasOwn.call( event, "namespace" ) ? event.namespace.split(".") : [];

        cur = tmp = elem = elem || document;

        // Don't do events on text and comment nodes
        if ( elem.nodeType === 3 || elem.nodeType === 8 ) {
            return;
        }

        // focus/blur morphs to focusin/out; ensure we're not firing them right now
        if ( rfocusMorph.test( type + jQuery.event.triggered ) ) {
            return;
        }

        if ( type.indexOf(".") >= 0 ) {
            // Namespaced trigger; create a regexp to match event type in handle()
            namespaces = type.split(".");
            type = namespaces.shift();
            namespaces.sort();
        }
        ontype = type.indexOf(":") < 0 && "on" + type;

        // Caller can pass in a jQuery.Event object, Object, or just an event type string
        event = event[ jQuery.expando ] ?
            event :
            new jQuery.Event( type, typeof event === "object" && event );

        // Trigger bitmask: & 1 for native handlers; & 2 for jQuery (always true)
        event.isTrigger = onlyHandlers ? 2 : 3;
        event.namespace = namespaces.join(".");
        event.namespace_re = event.namespace ?
            new RegExp( "(^|\\.)" + namespaces.join("\\.(?:.*\\.|)") + "(\\.|$)" ) :
            null;

        // Clean up the event in case it is being reused
        event.result = undefined;
        if ( !event.target ) {
            event.target = elem;
        }

        // Clone any incoming data and prepend the event, creating the handler arg list
        data = data == null ?
            [ event ] :
            jQuery.makeArray( data, [ event ] );

        // Allow special events to draw outside the lines
        special = jQuery.event.special[ type ] || {};
        if ( !onlyHandlers && special.trigger && special.trigger.apply( elem, data ) === false ) {
            return;
        }

        // Determine event propagation path in advance, per W3C events spec (#9951)
        // Bubble up to document, then to window; watch for a global ownerDocument var (#9724)
        if ( !onlyHandlers && !special.noBubble && !jQuery.isWindow( elem ) ) {

            bubbleType = special.delegateType || type;
            if ( !rfocusMorph.test( bubbleType + type ) ) {
                cur = cur.parentNode;
            }
            for ( ; cur; cur = cur.parentNode ) {
                eventPath.push( cur );
                tmp = cur;
            }

            // Only add window if we got to document (e.g., not plain obj or detached DOM)
            if ( tmp === (elem.ownerDocument || document) ) {
                eventPath.push( tmp.defaultView || tmp.parentWindow || window );
            }
        }

        // Fire handlers on the event path
        i = 0;
        while ( (cur = eventPath[i++]) && !event.isPropagationStopped() ) {

            event.type = i > 1 ?
                bubbleType :
                special.bindType || type;

            // jQuery handler
            handle = ( data_priv.get( cur, "events" ) || {} )[ event.type ] && data_priv.get( cur, "handle" );
            if ( handle ) {
                handle.apply( cur, data );
            }

            // Native handler
            handle = ontype && cur[ ontype ];
            if ( handle && jQuery.acceptData( cur ) && handle.apply && handle.apply( cur, data ) === false ) {
                event.preventDefault();
            }
        }
        event.type = type;

        // If nobody prevented the default action, do it now
        if ( !onlyHandlers && !event.isDefaultPrevented() ) {

            if ( (!special._default || special._default.apply( eventPath.pop(), data ) === false) &&
                jQuery.acceptData( elem ) ) {

                // Call a native DOM method on the target with the same name name as the event.
                // Don't do default actions on window, that's where global variables be (#6170)
                if ( ontype && jQuery.isFunction( elem[ type ] ) && !jQuery.isWindow( elem ) ) {

                    // Don't re-trigger an onFOO event when we call its FOO() method
                    tmp = elem[ ontype ];

                    if ( tmp ) {
                        elem[ ontype ] = null;
                    }

                    // Prevent re-triggering of the same event, since we already bubbled it above
                    jQuery.event.triggered = type;
                    elem[ type ]();
                    jQuery.event.triggered = undefined;

                    if ( tmp ) {
                        elem[ ontype ] = tmp;
                    }
                }
            }
        }

        return event.result;
    },

    dispatch: function( event ) {

        // Make a writable jQuery.Event from the native event object
        event = jQuery.event.fix( event );

        var i, j, ret, matched, handleObj,
            handlerQueue = [],
            args = core_slice.call( arguments ),
            handlers = ( data_priv.get( this, "events" ) || {} )[ event.type ] || [],
            special = jQuery.event.special[ event.type ] || {};

        // Use the fix-ed jQuery.Event rather than the (read-only) native event
        args[0] = event;
        event.delegateTarget = this;

        // Call the preDispatch hook for the mapped type, and let it bail if desired
        if ( special.preDispatch && special.preDispatch.call( this, event ) === false ) {
            return;
        }

        // Determine handlers
        handlerQueue = jQuery.event.handlers.call( this, event, handlers );

        // Run delegates first; they may want to stop propagation beneath us
        i = 0;
        while ( (matched = handlerQueue[ i++ ]) && !event.isPropagationStopped() ) {
            event.currentTarget = matched.elem;

            j = 0;
            while ( (handleObj = matched.handlers[ j++ ]) && !event.isImmediatePropagationStopped() ) {

                // Triggered event must either 1) have no namespace, or
                // 2) have namespace(s) a subset or equal to those in the bound event (both can have no namespace).
                if ( !event.namespace_re || event.namespace_re.test( handleObj.namespace ) ) {

                    event.handleObj = handleObj;
                    event.data = handleObj.data;

                    ret = ( (jQuery.event.special[ handleObj.origType ] || {}).handle || handleObj.handler )
                            .apply( matched.elem, args );

                    if ( ret !== undefined ) {
                        if ( (event.result = ret) === false ) {
                            event.preventDefault();
                            event.stopPropagation();
                        }
                    }
                }
            }
        }

        // Call the postDispatch hook for the mapped type
        if ( special.postDispatch ) {
            special.postDispatch.call( this, event );
        }

        return event.result;
    },

    handlers: function( event, handlers ) {
        var i, matches, sel, handleObj,
            handlerQueue = [],
            delegateCount = handlers.delegateCount,
            cur = event.target;

        // Find delegate handlers
        // Black-hole SVG <use> instance trees (#13180)
        // Avoid non-left-click bubbling in Firefox (#3861)
        if ( delegateCount && cur.nodeType && (!event.button || event.type !== "click") ) {

            for ( ; cur !== this; cur = cur.parentNode || this ) {

                // Don't process clicks on disabled elements (#6911, #8165, #11382, #11764)
                if ( cur.disabled !== true || event.type !== "click" ) {
                    matches = [];
                    for ( i = 0; i < delegateCount; i++ ) {
                        handleObj = handlers[ i ];

                        // Don't conflict with Object.prototype properties (#13203)
                        sel = handleObj.selector + " ";

                        if ( matches[ sel ] === undefined ) {
                            matches[ sel ] = handleObj.needsContext ?
                                jQuery( sel, this ).index( cur ) >= 0 :
                                jQuery.find( sel, this, null, [ cur ] ).length;
                        }
                        if ( matches[ sel ] ) {
                            matches.push( handleObj );
                        }
                    }
                    if ( matches.length ) {
                        handlerQueue.push({ elem: cur, handlers: matches });
                    }
                }
            }
        }

        // Add the remaining (directly-bound) handlers
        if ( delegateCount < handlers.length ) {
            handlerQueue.push({ elem: this, handlers: handlers.slice( delegateCount ) });
        }

        return handlerQueue;
    },

    // Includes some event props shared by KeyEvent and MouseEvent
    props: "altKey bubbles cancelable ctrlKey currentTarget eventPhase metaKey relatedTarget shiftKey target timeStamp view which".split(" "),

    fixHooks: {},

    keyHooks: {
        props: "char charCode key keyCode".split(" "),
        filter: function( event, original ) {

            // Add which for key events
            if ( event.which == null ) {
                event.which = original.charCode != null ? original.charCode : original.keyCode;
            }

            return event;
        }
    },

    mouseHooks: {
        props: "button buttons clientX clientY offsetX offsetY pageX pageY screenX screenY toElement".split(" "),
        filter: function( event, original ) {
            var eventDoc, doc, body,
                button = original.button;

            // Calculate pageX/Y if missing and clientX/Y available
            if ( event.pageX == null && original.clientX != null ) {
                eventDoc = event.target.ownerDocument || document;
                doc = eventDoc.documentElement;
                body = eventDoc.body;

                event.pageX = original.clientX + ( doc && doc.scrollLeft || body && body.scrollLeft || 0 ) - ( doc && doc.clientLeft || body && body.clientLeft || 0 );
                event.pageY = original.clientY + ( doc && doc.scrollTop  || body && body.scrollTop  || 0 ) - ( doc && doc.clientTop  || body && body.clientTop  || 0 );
            }

            // Add which for click: 1 === left; 2 === middle; 3 === right
            // Note: button is not normalized, so don't use it
            if ( !event.which && button !== undefined ) {
                event.which = ( button & 1 ? 1 : ( button & 2 ? 3 : ( button & 4 ? 2 : 0 ) ) );
            }

            return event;
        }
    },
  //对事件进行包裹
    fix: function( event ) {
        if ( event[ jQuery.expando ] ) {
            return event;//表明事件已经被包裹
        }

        // Create a writable copy of the event object and normalize some properties
        var i, prop, copy,
            type = event.type,
            //保存原始event
            originalEvent = event,
            fixHook = this.fixHooks[ type ];

        if ( !fixHook ) {
            this.fixHooks[ type ] = fixHook =
                rmouseEvent.test( type ) ? this.mouseHooks :
                rkeyEvent.test( type ) ? this.keyHooks :
                {};
        }
        copy = fixHook.props ? this.props.concat( fixHook.props ) : this.props;

        //克隆一个事件
        event = new jQuery.Event( originalEvent );

        i = copy.length;
        while ( i-- ) {
            prop = copy[ i ];
            event[ prop ] = originalEvent[ prop ];
        }

        // Support: Cordova 2.5 (WebKit) (#13255)
        // All events should have a target; Cordova deviceready doesn't
        if ( !event.target ) {
            event.target = document;
        }

        // Support: Safari 6.0+, Chrome < 28
        // Target should not be a text node (#504, #13143)
        if ( event.target.nodeType === 3 ) {
            event.target = event.target.parentNode;
        }

        return fixHook.filter? fixHook.filter( event, originalEvent ) : event;
    },

    special: {
        load: {
            // Prevent triggered image.load events from bubbling to window.load
            noBubble: true
        },
        focus: {
            // Fire native event if possible so blur/focus sequence is correct
            trigger: function() {
                if ( this !== safeActiveElement() && this.focus ) {
                    this.focus();
                    return false;
                }
            },
            delegateType: "focusin"
        },
        blur: {
            trigger: function() {
                if ( this === safeActiveElement() && this.blur ) {
                    this.blur();
                    return false;
                }
            },
            delegateType: "focusout"
        },
        click: {
            // For checkbox, fire native event so checked state will be right
            trigger: function() {
                if ( this.type === "checkbox" && this.click && jQuery.nodeName( this, "input" ) ) {
                    this.click();
                    return false;
                }
            },

            // For cross-browser consistency, don't fire native .click() on links
            _default: function( event ) {
                return jQuery.nodeName( event.target, "a" );
            }
        },

        beforeunload: {
            postDispatch: function( event ) {

                // Support: Firefox 20+
                // Firefox doesn't alert if the returnValue field is not set.
                if ( event.result !== undefined ) {
                    event.originalEvent.returnValue = event.result;
                }
            }
        }
    },

    simulate: function( type, elem, event, bubble ) {
        // Piggyback on a donor event to simulate a different one.
        // Fake originalEvent to avoid donor's stopPropagation, but if the
        // simulated event prevents default then we do the same on the donor.
        var e = jQuery.extend(
            new jQuery.Event(),
            event,
            {
                type: type,
                isSimulated: true,
                originalEvent: {}
            }
        );
        if ( bubble ) {
            jQuery.event.trigger( e, null, elem );
        } else {
            jQuery.event.dispatch.call( elem, e );
        }
        if ( e.isDefaultPrevented() ) {
            event.preventDefault();
        }
    }
};

jQuery.removeEvent = function( elem, type, handle ) {
    if ( elem.removeEventListener ) {
        elem.removeEventListener( type, handle, false );
    }
};

jQuery.Event = function( src, props ) {
    // Allow instantiation without the 'new' keyword
    if ( !(this instanceof jQuery.Event) ) {
        return new jQuery.Event( src, props );
    }

    // Event object
    if ( src && src.type ) {
        this.originalEvent = src;
        this.type = src.type;

        // Events bubbling up the document may have been marked as prevented
        // by a handler lower down the tree; reflect the correct value.
        this.isDefaultPrevented = ( src.defaultPrevented ||
            src.getPreventDefault && src.getPreventDefault() ) ? returnTrue : returnFalse;

    // Event type
    } else {
        this.type = src;
    }

    // Put explicitly provided properties onto the event object
    if ( props ) {
        jQuery.extend( this, props );
    }

    // Create a timestamp if incoming event doesn't have one
    this.timeStamp = src && src.timeStamp || jQuery.now();

    // Mark it as fixed
    this[ jQuery.expando ] = true;
};

// jQuery.Event is based on DOM3 Events as specified by the ECMAScript Language Binding
// http://www.w3.org/TR/2003/WD-DOM-Level-3-Events-20030331/ecma-script-binding.html
jQuery.Event.prototype = {
    isDefaultPrevented: returnFalse,
    isPropagationStopped: returnFalse,
    isImmediatePropagationStopped: returnFalse,

    preventDefault: function() {
        var e = this.originalEvent;

        this.isDefaultPrevented = returnTrue;

        if ( e && e.preventDefault ) {
            e.preventDefault();
        }
    },
    stopPropagation: function() {
        var e = this.originalEvent;

        this.isPropagationStopped = returnTrue;

        if ( e && e.stopPropagation ) {
            e.stopPropagation();
        }
    },
    stopImmediatePropagation: function() {
        this.isImmediatePropagationStopped = returnTrue;
        this.stopPropagation();
    }
};

// Create mouseenter/leave events using mouseover/out and event-time checks
// Support: Chrome 15+
jQuery.each({
    mouseenter: "mouseover",
    mouseleave: "mouseout"
}, function( orig, fix ) {
    jQuery.event.special[ orig ] = {
        delegateType: fix,
        bindType: fix,

        handle: function( event ) {
            var ret,
                target = this,
                related = event.relatedTarget,
                handleObj = event.handleObj;

            // For mousenter/leave call the handler if related is outside the target.
            // NB: No relatedTarget if the mouse left/entered the browser window
            if ( !related || (related !== target && !jQuery.contains( target, related )) ) {
                event.type = handleObj.origType;
                ret = handleObj.handler.apply( this, arguments );
                event.type = fix;
            }
            return ret;
        }
    };
});

// Create "bubbling" focus and blur events
// Support: Firefox, Chrome, Safari
if ( !jQuery.support.focusinBubbles ) {
    jQuery.each({ focus: "focusin", blur: "focusout" }, function( orig, fix ) {

        // Attach a single capturing handler while someone wants focusin/focusout
        var attaches = 0,
            handler = function( event ) {
                jQuery.event.simulate( fix, event.target, jQuery.event.fix( event ), true );
            };

        jQuery.event.special[ fix ] = {
            setup: function() {
                if ( attaches++ === 0 ) {
                    document.addEventListener( orig, handler, true );
                }
            },
            teardown: function() {
                if ( --attaches === 0 ) {
                    document.removeEventListener( orig, handler, true );
                }
            }
        };
    });
}

jQuery.fn.extend({

    on: function( types, selector, data, fn, /*INTERNAL*/ one ) {
        var origFn, type;

        // Types can be a map of types/handlers
        if ( typeof types === "object" ) {
            // ( types-Object, selector, data )
            if ( typeof selector !== "string" ) {
                // ( types-Object, data )
                data = data || selector;
                selector = undefined;
            }
            for ( type in types ) {
                this.on( type, selector, data, types[ type ], one );
            }
            return this;
        }

        if ( data == null && fn == null ) {
            // ( types, fn )
            fn = selector;
            data = selector = undefined;
        } else if ( fn == null ) {
            if ( typeof selector === "string" ) {
                // ( types, selector, fn )
                fn = data;
                data = undefined;
            } else {
                // ( types, data, fn )
                fn = data;
                data = selector;
                selector = undefined;
            }
        }
        if ( fn === false ) {
            fn = returnFalse;
        } else if ( !fn ) {
            return this;
        }

        if ( one === 1 ) {
            origFn = fn;
            fn = function( event ) {
                // Can use an empty set, since event contains the info
                jQuery().off( event );
                return origFn.apply( this, arguments );
            };
            // Use same guid so caller can remove using origFn
            fn.guid = origFn.guid || ( origFn.guid = jQuery.guid++ );
        }
        return this.each( function() {
            jQuery.event.add( this, types, fn, data, selector );
        });
    },
    one: function( types, selector, data, fn ) {
        return this.on( types, selector, data, fn, 1 );
    },
    off: function( types, selector, fn ) {
        var handleObj, type;
        if ( types && types.preventDefault && types.handleObj ) {
            // ( event )  dispatched jQuery.Event
            handleObj = types.handleObj;
            jQuery( types.delegateTarget ).off(
                handleObj.namespace ? handleObj.origType + "." + handleObj.namespace : handleObj.origType,
                handleObj.selector,
                handleObj.handler
            );
            return this;
        }
        if ( typeof types === "object" ) {
            // ( types-object [, selector] )
            for ( type in types ) {
                this.off( type, selector, types[ type ] );
            }
            return this;
        }
        if ( selector === false || typeof selector === "function" ) {
            // ( types [, fn] )
            fn = selector;
            selector = undefined;
        }
        if ( fn === false ) {
            fn = returnFalse;
        }
        return this.each(function() {
            jQuery.event.remove( this, types, fn, selector );
        });
    },

    trigger: function( type, data ) {
        return this.each(function() {
            jQuery.event.trigger( type, data, this );
        });
    },
    triggerHandler: function( type, data ) {
        var elem = this[0];
        if ( elem ) {
            return jQuery.event.trigger( type, data, elem, true );
        }
    }
});
var isSimple = /^.[^:#\[\.,]*$/,
    rparentsprev = /^(?:parents|prev(?:Until|All))/,
    rneedsContext = jQuery.expr.match.needsContext,
    // methods guaranteed to produce a unique set when starting from a unique set
    guaranteedUnique = {
        children: true,
        contents: true,
        next: true,
        prev: true
    };

jQuery.fn.extend({
    find: function( selector ) {
        var i,
            ret = [],
            self = this,
            len = self.length;

        if ( typeof selector !== "string" ) {
            return this.pushStack( jQuery( selector ).filter(function() {
                for ( i = 0; i < len; i++ ) {
                    if ( jQuery.contains( self[ i ], this ) ) {
                        return true;
                    }
                }
            }) );
        }

        for ( i = 0; i < len; i++ ) {
            jQuery.find( selector, self[ i ], ret );
        }

        // Needed because $( selector, context ) becomes $( context ).find( selector )
        ret = this.pushStack( len > 1 ? jQuery.unique( ret ) : ret );
        ret.selector = this.selector ? this.selector + " " + selector : selector;
        return ret;
    },

    has: function( target ) {
        var targets = jQuery( target, this ),
            l = targets.length;

        return this.filter(function() {
            var i = 0;
            for ( ; i < l; i++ ) {
                if ( jQuery.contains( this, targets[i] ) ) {
                    return true;
                }
            }
        });
    },

    not: function( selector ) {
        return this.pushStack( winnow(this, selector || [], true) );
    },

    filter: function( selector ) {
        return this.pushStack( winnow(this, selector || [], false) );
    },

    is: function( selector ) {
        return !!winnow(
            this,

            // If this is a positional/relative selector, check membership in the returned set
            // so $("p:first").is("p:last") won't return true for a doc with two "p".
            typeof selector === "string" && rneedsContext.test( selector ) ?
                jQuery( selector ) :
                selector || [],
            false
        ).length;
    },

    closest: function( selectors, context ) {
        var cur,
            i = 0,
            l = this.length,
            matched = [],
            pos = ( rneedsContext.test( selectors ) || typeof selectors !== "string" ) ?
                jQuery( selectors, context || this.context ) :
                0;

        for ( ; i < l; i++ ) {
            for ( cur = this[i]; cur && cur !== context; cur = cur.parentNode ) {
                // Always skip document fragments
                if ( cur.nodeType < 11 && (pos ?
                    pos.index(cur) > -1 :

                    // Don't pass non-elements to Sizzle
                    cur.nodeType === 1 &&
                        jQuery.find.matchesSelector(cur, selectors)) ) {

                    cur = matched.push( cur );
                    break;
                }
            }
        }

        return this.pushStack( matched.length > 1 ? jQuery.unique( matched ) : matched );
    },

    // Determine the position of an element within
    // the matched set of elements
    index: function( elem ) {

        // No argument, return index in parent
        if ( !elem ) {
            return ( this[ 0 ] && this[ 0 ].parentNode ) ? this.first().prevAll().length : -1;
        }

        // index in selector
        if ( typeof elem === "string" ) {
            return core_indexOf.call( jQuery( elem ), this[ 0 ] );
        }

        // Locate the position of the desired element
        return core_indexOf.call( this,

            // If it receives a jQuery object, the first element is used
            elem.jquery ? elem[ 0 ] : elem
        );
    },

    add: function( selector, context ) {
        var set = typeof selector === "string" ?
                jQuery( selector, context ) :
                jQuery.makeArray( selector && selector.nodeType ? [ selector ] : selector ),
            all = jQuery.merge( this.get(), set );

        return this.pushStack( jQuery.unique(all) );
    },

    addBack: function( selector ) {
        return this.add( selector == null ?
            this.prevObject : this.prevObject.filter(selector)
        );
    }
});

function sibling( cur, dir ) {
    while ( (cur = cur[dir]) && cur.nodeType !== 1 ) {}

    return cur;
}

jQuery.each({
    parent: function( elem ) {
        var parent = elem.parentNode;
        return parent && parent.nodeType !== 11 ? parent : null;
    },
    parents: function( elem ) {
        return jQuery.dir( elem, "parentNode" );
    },
    parentsUntil: function( elem, i, until ) {
        return jQuery.dir( elem, "parentNode", until );
    },
    next: function( elem ) {
        return sibling( elem, "nextSibling" );
    },
    prev: function( elem ) {
        return sibling( elem, "previousSibling" );
    },
    nextAll: function( elem ) {
        return jQuery.dir( elem, "nextSibling" );
    },
    prevAll: function( elem ) {
        return jQuery.dir( elem, "previousSibling" );
    },
    nextUntil: function( elem, i, until ) {
        return jQuery.dir( elem, "nextSibling", until );
    },
    prevUntil: function( elem, i, until ) {
        return jQuery.dir( elem, "previousSibling", until );
    },
    siblings: function( elem ) {
        return jQuery.sibling( ( elem.parentNode || {} ).firstChild, elem );
    },
    children: function( elem ) {
        return jQuery.sibling( elem.firstChild );
    },
    contents: function( elem ) {
        return elem.contentDocument || jQuery.merge( [], elem.childNodes );
    }
}, function( name, fn ) {
    jQuery.fn[ name ] = function( until, selector ) {
        var matched = jQuery.map( this, fn, until );

        if ( name.slice( -5 ) !== "Until" ) {
            selector = until;
        }

        if ( selector && typeof selector === "string" ) {
            matched = jQuery.filter( selector, matched );
        }

        if ( this.length > 1 ) {
            // Remove duplicates
            if ( !guaranteedUnique[ name ] ) {
                jQuery.unique( matched );
            }

            // Reverse order for parents* and prev-derivatives
            if ( rparentsprev.test( name ) ) {
                matched.reverse();
            }
        }

        return this.pushStack( matched );
    };
});

jQuery.extend({
    filter: function( expr, elems, not ) {
        var elem = elems[ 0 ];

        if ( not ) {
            expr = ":not(" + expr + ")";
        }

        return elems.length === 1 && elem.nodeType === 1 ?
            jQuery.find.matchesSelector( elem, expr ) ? [ elem ] : [] :
            jQuery.find.matches( expr, jQuery.grep( elems, function( elem ) {
                return elem.nodeType === 1;
            }));
    },

    dir: function( elem, dir, until ) {
        var matched = [],
            truncate = until !== undefined;

        while ( (elem = elem[ dir ]) && elem.nodeType !== 9 ) {
            if ( elem.nodeType === 1 ) {
                if ( truncate && jQuery( elem ).is( until ) ) {
                    break;
                }
                matched.push( elem );
            }
        }
        return matched;
    },

    sibling: function( n, elem ) {
        var matched = [];

        for ( ; n; n = n.nextSibling ) {
            if ( n.nodeType === 1 && n !== elem ) {
                matched.push( n );
            }
        }

        return matched;
    }
});

// Implement the identical functionality for filter and not
function winnow( elements, qualifier, not ) {
    if ( jQuery.isFunction( qualifier ) ) {
        return jQuery.grep( elements, function( elem, i ) {
            /* jshint -W018 */
            return !!qualifier.call( elem, i, elem ) !== not;
        });

    }

    if ( qualifier.nodeType ) {
        return jQuery.grep( elements, function( elem ) {
            return ( elem === qualifier ) !== not;
        });

    }

    if ( typeof qualifier === "string" ) {
        if ( isSimple.test( qualifier ) ) {
            return jQuery.filter( qualifier, elements, not );
        }

        qualifier = jQuery.filter( qualifier, elements );
    }

    return jQuery.grep( elements, function( elem ) {
        return ( core_indexOf.call( qualifier, elem ) >= 0 ) !== not;
    });
}
var rxhtmlTag = /<(?!area|br|col|embed|hr|img|input|link|meta|param)(([\w:]+)[^>]*)\/>/gi,
    rtagName = /<([\w:]+)/,
    rhtml = /<|&#?\w+;/,
    rnoInnerhtml = /<(?:script|style|link)/i,
    manipulation_rcheckableType = /^(?:checkbox|radio)$/i,
    // checked="checked" or checked
    rchecked = /checked\s*(?:[^=]|=\s*.checked.)/i,
    rscriptType = /^$|\/(?:java|ecma)script/i,
    rscriptTypeMasked = /^true\/(.*)/,
    rcleanScript = /^\s*<!(?:\[CDATA\[|--)|(?:\]\]|--)>\s*$/g,

    // We have to close these tags to support XHTML (#13200)
    wrapMap = {

        // Support: IE 9
        option: [ 1, "<select multiple='multiple'>", "</select>" ],

        thead: [ 1, "<table>", "</table>" ],
        col: [ 2, "<table><colgroup>", "</colgroup></table>" ],
        tr: [ 2, "<table><tbody>", "</tbody></table>" ],
        td: [ 3, "<table><tbody><tr>", "</tr></tbody></table>" ],

        _default: [ 0, "", "" ]
    };

// Support: IE 9
wrapMap.optgroup = wrapMap.option;

wrapMap.tbody = wrapMap.tfoot = wrapMap.colgroup = wrapMap.caption = wrapMap.thead;
wrapMap.th = wrapMap.td;

jQuery.fn.extend({
    text: function( value ) {
        return jQuery.access( this, function( value ) {
            return value === undefined ?
                jQuery.text( this ) :
                this.empty().append( ( this[ 0 ] && this[ 0 ].ownerDocument || document ).createTextNode( value ) );
        }, null, value, arguments.length );
    },

    append: function() {
        return this.domManip( arguments, function( elem ) {
            if ( this.nodeType === 1 || this.nodeType === 11 || this.nodeType === 9 ) {
                var target = manipulationTarget( this, elem );
                target.appendChild( elem );
            }
        });
    },

    prepend: function() {
        return this.domManip( arguments, function( elem ) {
            if ( this.nodeType === 1 || this.nodeType === 11 || this.nodeType === 9 ) {
                var target = manipulationTarget( this, elem );
                target.insertBefore( elem, target.firstChild );
            }
        });
    },

    before: function() {
        return this.domManip( arguments, function( elem ) {
            if ( this.parentNode ) {
                this.parentNode.insertBefore( elem, this );
            }
        });
    },

    after: function() {
        return this.domManip( arguments, function( elem ) {
            if ( this.parentNode ) {
                this.parentNode.insertBefore( elem, this.nextSibling );
            }
        });
    },

    // keepData is for internal use only--do not document
    remove: function( selector, keepData ) {
        var elem,
            elems = selector ? jQuery.filter( selector, this ) : this,
            i = 0;

        for ( ; (elem = elems[i]) != null; i++ ) {
            if ( !keepData && elem.nodeType === 1 ) {
                jQuery.cleanData( getAll( elem ) );
            }

            if ( elem.parentNode ) {
                if ( keepData && jQuery.contains( elem.ownerDocument, elem ) ) {
                    setGlobalEval( getAll( elem, "script" ) );
                }
                elem.parentNode.removeChild( elem );
            }
        }

        return this;
    },

    empty: function() {
        var elem,
            i = 0;

        for ( ; (elem = this[i]) != null; i++ ) {
            if ( elem.nodeType === 1 ) {

                // Prevent memory leaks
                jQuery.cleanData( getAll( elem, false ) );

                // Remove any remaining nodes
                elem.textContent = "";
            }
        }

        return this;
    },

    clone: function( dataAndEvents, deepDataAndEvents ) {
        dataAndEvents = dataAndEvents == null ? false : dataAndEvents;
        deepDataAndEvents = deepDataAndEvents == null ? dataAndEvents : deepDataAndEvents;

        return this.map( function () {
            return jQuery.clone( this, dataAndEvents, deepDataAndEvents );
        });
    },

    html: function( value ) {
        return jQuery.access( this, function( value ) {
            var elem = this[ 0 ] || {},
                i = 0,
                l = this.length;

            if ( value === undefined && elem.nodeType === 1 ) {
                return elem.innerHTML;
            }

            // See if we can take a shortcut and just use innerHTML
            if ( typeof value === "string" && !rnoInnerhtml.test( value ) &&
                !wrapMap[ ( rtagName.exec( value ) || [ "", "" ] )[ 1 ].toLowerCase() ] ) {

                value = value.replace( rxhtmlTag, "<$1></$2>" );

                try {
                    for ( ; i < l; i++ ) {
                        elem = this[ i ] || {};

                        // Remove element nodes and prevent memory leaks
                        if ( elem.nodeType === 1 ) {
                            jQuery.cleanData( getAll( elem, false ) );
                            elem.innerHTML = value;
                        }
                    }

                    elem = 0;

                // If using innerHTML throws an exception, use the fallback method
                } catch( e ) {}
            }

            if ( elem ) {
                this.empty().append( value );
            }
        }, null, value, arguments.length );
    },

    replaceWith: function() {
        var
            // Snapshot the DOM in case .domManip sweeps something relevant into its fragment
            args = jQuery.map( this, function( elem ) {
                return [ elem.nextSibling, elem.parentNode ];
            }),
            i = 0;

        // Make the changes, replacing each context element with the new content
        this.domManip( arguments, function( elem ) {
            var next = args[ i++ ],
                parent = args[ i++ ];

            if ( parent ) {
                // Don't use the snapshot next if it has moved (#13810)
                if ( next && next.parentNode !== parent ) {
                    next = this.nextSibling;
                }
                jQuery( this ).remove();
                parent.insertBefore( elem, next );
            }
        // Allow new content to include elements from the context set
        }, true );

        // Force removal if there was no new content (e.g., from empty arguments)
        return i ? this : this.remove();
    },

    detach: function( selector ) {
        return this.remove( selector, true );
    },

    domManip: function( args, callback, allowIntersection ) {

        // Flatten any nested arrays
        args = core_concat.apply( [], args );

        var fragment, first, scripts, hasScripts, node, doc,
            i = 0,
            l = this.length,
            set = this,
            iNoClone = l - 1,//是否为克隆节点
            value = args[ 0 ],
            isFunction = jQuery.isFunction( value );

        // We can't cloneNode fragments that contain checked, in WebKit
        if ( isFunction || !( l <= 1 || typeof value !== "string" || jQuery.support.checkClone || !rchecked.test( value ) ) ) {
            return this.each(function( index ) {
                var self = set.eq( index );
                if ( isFunction ) {
                    args[ 0 ] = value.call( this, index, self.html() );
                }
                self.domManip( args, callback, allowIntersection );
            });
        }

        if ( l ) {
            fragment = jQuery.buildFragment( args, this[ 0 ].ownerDocument, false, !allowIntersection && this );
            first = fragment.firstChild;

            if ( fragment.childNodes.length === 1 ) {
                fragment = first;
            }

            if ( first ) {
                scripts = jQuery.map( getAll( fragment, "script" ), disableScript );
                hasScripts = scripts.length;

                // Use the original fragment for the last item instead of the first because it can end up
                // being emptied incorrectly in certain situations (#8070).
                for ( ; i < l; i++ ) {
                    node = fragment;

                    if ( i !== iNoClone ) {
                        node = jQuery.clone( node, true, true );

                        // Keep references to cloned scripts for later restoration
                        if ( hasScripts ) {
                            // Support: QtWebKit
                            // jQuery.merge because core_push.apply(_, arraylike) throws
                            jQuery.merge( scripts, getAll( node, "script" ) );
                        }
                    }

                    callback.call( this[ i ], node, i );
                }

                if ( hasScripts ) {
                    doc = scripts[ scripts.length - 1 ].ownerDocument;

                    // Reenable scripts
                    jQuery.map( scripts, restoreScript );

                    // Evaluate executable scripts on first document insertion
                    for ( i = 0; i < hasScripts; i++ ) {
                        node = scripts[ i ];
                        if ( rscriptType.test( node.type || "" ) &&
                            !data_priv.access( node, "globalEval" ) && jQuery.contains( doc, node ) ) {

                            if ( node.src ) {
                                // Hope ajax is available...
                                jQuery._evalUrl( node.src );
                            } else {
                                jQuery.globalEval( node.textContent.replace( rcleanScript, "" ) );
                            }
                        }
                    }
                }
            }
        }

        return this;
    }
});

jQuery.each({
    appendTo: "append",
    prependTo: "prepend",
    insertBefore: "before",
    insertAfter: "after",
    replaceAll: "replaceWith"
}, function( name, original ) {
    jQuery.fn[ name ] = function( selector ) {
        var elems,
            ret = [],
            insert = jQuery( selector ),
            last = insert.length - 1,
            i = 0;

        for ( ; i <= last; i++ ) {
            elems = i === last ? this : this.clone( true );
            jQuery( insert[ i ] )[ original ]( elems );

            // Support: QtWebKit
            // .get() because core_push.apply(_, arraylike) throws
            core_push.apply( ret, elems.get() );
        }

        return this.pushStack( ret );
    };
});

jQuery.extend({
    clone: function( elem, dataAndEvents, deepDataAndEvents ) {
        var i, l, srcElements, destElements,
            clone = elem.cloneNode( true ),
            inPage = jQuery.contains( elem.ownerDocument, elem );

        // Support: IE >= 9
        // Fix Cloning issues
        if ( !jQuery.support.noCloneChecked && ( elem.nodeType === 1 || elem.nodeType === 11 ) && !jQuery.isXMLDoc( elem ) ) {

            // We eschew Sizzle here for performance reasons: http://jsperf.com/getall-vs-sizzle/2
            destElements = getAll( clone );
            srcElements = getAll( elem );

            for ( i = 0, l = srcElements.length; i < l; i++ ) {
                fixInput( srcElements[ i ], destElements[ i ] );
            }
        }

        // Copy the events from the original to the clone
        if ( dataAndEvents ) {
            if ( deepDataAndEvents ) {
                srcElements = srcElements || getAll( elem );
                destElements = destElements || getAll( clone );

                for ( i = 0, l = srcElements.length; i < l; i++ ) {
                    cloneCopyEvent( srcElements[ i ], destElements[ i ] );
                }
            } else {
                cloneCopyEvent( elem, clone );
            }
        }

        // Preserve script evaluation history
        destElements = getAll( clone, "script" );
        if ( destElements.length > 0 ) {
            setGlobalEval( destElements, !inPage && getAll( elem, "script" ) );
        }

        // Return the cloned set
        return clone;
    },

    buildFragment: function( elems, context, scripts, selection ) {
        var elem, tmp, tag, wrap, contains, j,
            i = 0,
            l = elems.length,
            fragment = context.createDocumentFragment(),
            nodes = [];

        for ( ; i < l; i++ ) {
            elem = elems[ i ];

            if ( elem || elem === 0 ) {

                // Add nodes directly
                if ( jQuery.type( elem ) === "object" ) {
                    // Support: QtWebKit
                    // jQuery.merge because core_push.apply(_, arraylike) throws
                    jQuery.merge( nodes, elem.nodeType ? [ elem ] : elem );

                // Convert non-html into a text node
                } else if ( !rhtml.test( elem ) ) {
                    nodes.push( context.createTextNode( elem ) );

                // Convert html into DOM nodes
                } else {
                    tmp = tmp || fragment.appendChild( context.createElement("div") );

                    // Deserialize a standard representation
                    tag = ( rtagName.exec( elem ) || ["", ""] )[ 1 ].toLowerCase();
                    wrap = wrapMap[ tag ] || wrapMap._default;
                    tmp.innerHTML = wrap[ 1 ] + elem.replace( rxhtmlTag, "<$1></$2>" ) + wrap[ 2 ];

                    // Descend through wrappers to the right content
                    j = wrap[ 0 ];
                    while ( j-- ) {
                        tmp = tmp.lastChild;
                    }

                    // Support: QtWebKit
                    // jQuery.merge because core_push.apply(_, arraylike) throws
                    jQuery.merge( nodes, tmp.childNodes );

                    // Remember the top-level container
                    tmp = fragment.firstChild;

                    // Fixes #12346
                    // Support: Webkit, IE
                    tmp.textContent = "";
                }
            }
        }

        // Remove wrapper from fragment
        fragment.textContent = "";

        i = 0;
        while ( (elem = nodes[ i++ ]) ) {

            // #4087 - If origin and destination elements are the same, and this is
            // that element, do not do anything
            if ( selection && jQuery.inArray( elem, selection ) !== -1 ) {
                continue;
            }

            contains = jQuery.contains( elem.ownerDocument, elem );

            // Append to fragment
            tmp = getAll( fragment.appendChild( elem ), "script" );

            // Preserve script evaluation history
            if ( contains ) {
                setGlobalEval( tmp );
            }

            // Capture executables
            if ( scripts ) {
                j = 0;
                while ( (elem = tmp[ j++ ]) ) {
                    if ( rscriptType.test( elem.type || "" ) ) {
                        scripts.push( elem );
                    }
                }
            }
        }

        return fragment;
    },

    cleanData: function( elems ) {
        var data, elem, events, type, key, j,
            special = jQuery.event.special,
            i = 0;

        for ( ; (elem = elems[ i ]) !== undefined; i++ ) {
            if ( Data.accepts( elem ) ) {
                key = elem[ data_priv.expando ];

                if ( key && (data = data_priv.cache[ key ]) ) {
                    events = Object.keys( data.events || {} );
                    if ( events.length ) {
                        for ( j = 0; (type = events[j]) !== undefined; j++ ) {
                            if ( special[ type ] ) {
                                jQuery.event.remove( elem, type );

                            // This is a shortcut to avoid jQuery.event.remove's overhead
                            } else {
                                jQuery.removeEvent( elem, type, data.handle );
                            }
                        }
                    }
                    if ( data_priv.cache[ key ] ) {
                        // Discard any remaining `private` data
                        delete data_priv.cache[ key ];
                    }
                }
            }
            // Discard any remaining `user` data
            delete data_user.cache[ elem[ data_user.expando ] ];
        }
    },

    _evalUrl: function( url ) {
        return jQuery.ajax({
            url: url,
            type: "GET",
            dataType: "script",
            async: false,
            global: false,
            "throws": true
        });
    }
});

// Support: 1.x compatibility
// Manipulating tables requires a tbody
function manipulationTarget( elem, content ) {
    return jQuery.nodeName( elem, "table" ) &&
        jQuery.nodeName( content.nodeType === 1 ? content : content.firstChild, "tr" ) ?

        elem.getElementsByTagName("tbody")[0] ||
            elem.appendChild( elem.ownerDocument.createElement("tbody") ) :
        elem;
}

// Replace/restore the type attribute of script elements for safe DOM manipulation
function disableScript( elem ) {
    elem.type = (elem.getAttribute("type") !== null) + "/" + elem.type;
    return elem;
}
function restoreScript( elem ) {
    var match = rscriptTypeMasked.exec( elem.type );

    if ( match ) {
        elem.type = match[ 1 ];
    } else {
        elem.removeAttribute("type");
    }

    return elem;
}

// Mark scripts as having already been evaluated
function setGlobalEval( elems, refElements ) {
    var l = elems.length,
        i = 0;

    for ( ; i < l; i++ ) {
        data_priv.set(
            elems[ i ], "globalEval", !refElements || data_priv.get( refElements[ i ], "globalEval" )
        );
    }
}

function cloneCopyEvent( src, dest ) {
    var i, l, type, pdataOld, pdataCur, udataOld, udataCur, events;

    if ( dest.nodeType !== 1 ) {
        return;
    }

    // 1. Copy private data: events, handlers, etc.
    if ( data_priv.hasData( src ) ) {
        pdataOld = data_priv.access( src );
        pdataCur = data_priv.set( dest, pdataOld );
        events = pdataOld.events;

        if ( events ) {
            delete pdataCur.handle;
            pdataCur.events = {};

            for ( type in events ) {
                for ( i = 0, l = events[ type ].length; i < l; i++ ) {
                    jQuery.event.add( dest, type, events[ type ][ i ] );
                }
            }
        }
    }

    // 2. Copy user data
    if ( data_user.hasData( src ) ) {
        udataOld = data_user.access( src );
        udataCur = jQuery.extend( {}, udataOld );

        data_user.set( dest, udataCur );
    }
}


function getAll( context, tag ) { //这是一个jQuery内部使用的函数,非常有用。他获取context中(自身以及后代节点)标签名为tag的节点集合。他使用context.getElementsByTagName或context.querySelectorAll来获取,当实在是没有获取到值的时候通过context.childNodes来获取conten的儿子节点中标签为tag的节点。
    var ret = context.getElementsByTagName ? context.getElementsByTagName( tag || "*" ) :
            context.querySelectorAll ? context.querySelectorAll( tag || "*" ) :
            [];

    return tag === undefined || tag && jQuery.nodeName( context, tag ) ?
        jQuery.merge( [ context ], ret ) :
        ret;
}

// Support: IE >= 9
function fixInput( src, dest ) {
    var nodeName = dest.nodeName.toLowerCase();

    // Fails to persist the checked state of a cloned checkbox or radio button.
    if ( nodeName === "input" && manipulation_rcheckableType.test( src.type ) ) {
        dest.checked = src.checked;

    // Fails to return the selected option to the default selected state when cloning options
    } else if ( nodeName === "input" || nodeName === "textarea" ) {
        dest.defaultValue = src.defaultValue;
    }
}
jQuery.fn.extend({
    wrapAll: function( html ) {
        var wrap;

        if ( jQuery.isFunction( html ) ) {
            return this.each(function( i ) {
                jQuery( this ).wrapAll( html.call(this, i) );
            });
        }

        if ( this[ 0 ] ) {

            // The elements to wrap the target around
            wrap = jQuery( html, this[ 0 ].ownerDocument ).eq( 0 ).clone( true );

            if ( this[ 0 ].parentNode ) {
                wrap.insertBefore( this[ 0 ] );
            }

            wrap.map(function() {
                var elem = this;

                while ( elem.firstElementChild ) {
                    elem = elem.firstElementChild;
                }

                return elem;
            }).append( this );
        }

        return this;
    },

    wrapInner: function( html ) {
        if ( jQuery.isFunction( html ) ) {
            return this.each(function( i ) {
                jQuery( this ).wrapInner( html.call(this, i) );
            });
        }

        return this.each(function() {
            var self = jQuery( this ),
                contents = self.contents();

            if ( contents.length ) {
                contents.wrapAll( html );

            } else {
                self.append( html );
            }
        });
    },

    wrap: function( html ) {
        var isFunction = jQuery.isFunction( html );

        return this.each(function( i ) {
            jQuery( this ).wrapAll( isFunction ? html.call(this, i) : html );
        });
    },

    unwrap: function() {
        return this.parent().each(function() {
            if ( !jQuery.nodeName( this, "body" ) ) {
                jQuery( this ).replaceWith( this.childNodes );
            }
        }).end();
    }
});
var curCSS, iframe,
    // swappable if display is none or starts with table except "table", "table-cell", or "table-caption"
    // see here for display values: https://developer.mozilla.org/en-US/docs/CSS/display
    rdisplayswap = /^(none|table(?!-c[ea]).+)/,
    rmargin = /^margin/,
    rnumsplit = new RegExp( "^(" + core_pnum + ")(.*)$", "i" ),
    rnumnonpx = new RegExp( "^(" + core_pnum + ")(?!px)[a-z%]+$", "i" ),
    rrelNum = new RegExp( "^([+-])=(" + core_pnum + ")", "i" ),
    elemdisplay = { BODY: "block" },

    cssShow = { position: "absolute", visibility: "hidden", display: "block" },
    cssNormalTransform = {
        letterSpacing: 0,
        fontWeight: 400
    },

    cssExpand = [ "Top", "Right", "Bottom", "Left" ],
    cssPrefixes = [ "Webkit", "O", "Moz", "ms" ];

// return a css property mapped to a potentially vendor prefixed property
function vendorPropName( style, name ) {

    // shortcut for names that are not vendor prefixed
    if ( name in style ) {
        return name;
    }

    // check for vendor prefixed names
    var capName = name.charAt(0).toUpperCase() + name.slice(1),
        origName = name,
        i = cssPrefixes.length;

    while ( i-- ) {
        name = cssPrefixes[ i ] + capName;
        if ( name in style ) {
            return name;
        }
    }

    return origName;
}

function isHidden( elem, el ) {
    // isHidden might be called from jQuery#filter function;
    // in that case, element will be second argument
    elem = el || elem;
    return jQuery.css( elem, "display" ) === "none" || !jQuery.contains( elem.ownerDocument, elem );
}

// NOTE: we've included the "window" in window.getComputedStyle
// because jsdom on node.js will break without it.
function getStyles( elem ) {
    return window.getComputedStyle( elem, null );
}

function showHide( elements, show ) {
    var display, elem, hidden,
        values = [],
        index = 0,
        length = elements.length;

    for ( ; index < length; index++ ) {
        elem = elements[ index ];
        if ( !elem.style ) {
            continue;
        }

        values[ index ] = data_priv.get( elem, "olddisplay" );
        display = elem.style.display;
        if ( show ) {
            // Reset the inline display of this element to learn if it is
            // being hidden by cascaded rules or not
            if ( !values[ index ] && display === "none" ) {
                elem.style.display = "";
            }

            // Set elements which have been overridden with display: none
            // in a stylesheet to whatever the default browser style is
            // for such an element
            if ( elem.style.display === "" && isHidden( elem ) ) {
                values[ index ] = data_priv.access( elem, "olddisplay", css_defaultDisplay(elem.nodeName) );
            }
        } else {

            if ( !values[ index ] ) {
                hidden = isHidden( elem );

                if ( display && display !== "none" || !hidden ) {
                    data_priv.set( elem, "olddisplay", hidden ? display : jQuery.css(elem, "display") );
                }
            }
        }
    }

    // Set the display of most of the elements in a second loop
    // to avoid the constant reflow
    for ( index = 0; index < length; index++ ) {
        elem = elements[ index ];
        if ( !elem.style ) {
            continue;
        }
        if ( !show || elem.style.display === "none" || elem.style.display === "" ) {
            elem.style.display = show ? values[ index ] || "" : "none";
        }
    }

    return elements;
}

jQuery.fn.extend({
    css: function( name, value ) {
        return jQuery.access( this, function( elem, name, value ) {
            var styles, len,
                map = {},
                i = 0;

            if ( jQuery.isArray( name ) ) {
                styles = getStyles( elem );
                len = name.length;

                for ( ; i < len; i++ ) {
                    map[ name[ i ] ] = jQuery.css( elem, name[ i ], false, styles );
                }

                return map;
            }

            return value !== undefined ?
                jQuery.style( elem, name, value ) :
                jQuery.css( elem, name );
        }, name, value, arguments.length > 1 );
    },
    show: function() {
        return showHide( this, true );
    },
    hide: function() {
        return showHide( this );
    },
    toggle: function( state ) {
        if ( typeof state === "boolean" ) {
            return state ? this.show() : this.hide();
        }

        return this.each(function() {
            if ( isHidden( this ) ) {
                jQuery( this ).show();
            } else {
                jQuery( this ).hide();
            }
        });
    }
});

jQuery.extend({
    // Add in style property hooks for overriding the default
    // behavior of getting and setting a style property
    cssHooks: {
        opacity: {
            get: function( elem, computed ) {
                if ( computed ) {
                    // We should always get a number back from opacity
                    var ret = curCSS( elem, "opacity" );
                    return ret === "" ? "1" : ret;
                }
            }
        }
    },

    // Don't automatically add "px" to these possibly-unitless properties
    cssNumber: {
        "columnCount": true,
        "fillOpacity": true,
        "fontWeight": true,
        "lineHeight": true,
        "opacity": true,
        "order": true,
        "orphans": true,
        "widows": true,
        "zIndex": true,
        "zoom": true
    },

    // Add in properties whose names you wish to fix before
    // setting or getting the value
    cssProps: {
        // normalize float css property
        "float": "cssFloat"
    },

    // Get and set the style property on a DOM Node
    style: function( elem, name, value, extra ) {
        // Don't set styles on text and comment nodes
        if ( !elem || elem.nodeType === 3 || elem.nodeType === 8 || !elem.style ) {
            return;
        }

        // Make sure that we're working with the right name
        var ret, type, hooks,
            origName = jQuery.camelCase( name ),
            style = elem.style;

        name = jQuery.cssProps[ origName ] || ( jQuery.cssProps[ origName ] = vendorPropName( style, origName ) );

        // gets hook for the prefixed version
        // followed by the unprefixed version
        hooks = jQuery.cssHooks[ name ] || jQuery.cssHooks[ origName ];

        // Check if we're setting a value
        if ( value !== undefined ) {
            type = typeof value;

            // convert relative number strings (+= or -=) to relative numbers. #7345
            if ( type === "string" && (ret = rrelNum.exec( value )) ) {
                value = ( ret[1] + 1 ) * ret[2] + parseFloat( jQuery.css( elem, name ) );
                // Fixes bug #9237
                type = "number";
            }

            // Make sure that NaN and null values aren't set. See: #7116
            if ( value == null || type === "number" && isNaN( value ) ) {
                return;
            }

            // If a number was passed in, add 'px' to the (except for certain CSS properties)
            if ( type === "number" && !jQuery.cssNumber[ origName ] ) {
                value += "px";
            }

            // Fixes #8908, it can be done more correctly by specifying setters in cssHooks,
            // but it would mean to define eight (for every problematic property) identical functions
            if ( !jQuery.support.clearCloneStyle && value === "" && name.indexOf("background") === 0 ) {
                style[ name ] = "inherit";
            }

            // If a hook was provided, use that value, otherwise just set the specified value
            if ( !hooks || !("set" in hooks) || (value = hooks.set( elem, value, extra )) !== undefined ) {
                style[ name ] = value;
            }

        } else {
            // If a hook was provided get the non-computed value from there
            if ( hooks && "get" in hooks && (ret = hooks.get( elem, false, extra )) !== undefined ) {
                return ret;
            }

            // Otherwise just get the value from the style object
            return style[ name ];
        }
    },

    css: function( elem, name, extra, styles ) {
        var val, num, hooks,
            origName = jQuery.camelCase( name );

        // Make sure that we're working with the right name
        name = jQuery.cssProps[ origName ] || ( jQuery.cssProps[ origName ] = vendorPropName( elem.style, origName ) );

        // gets hook for the prefixed version
        // followed by the unprefixed version
        hooks = jQuery.cssHooks[ name ] || jQuery.cssHooks[ origName ];

        // If a hook was provided get the computed value from there
        if ( hooks && "get" in hooks ) {
            val = hooks.get( elem, true, extra );
        }

        // Otherwise, if a way to get the computed value exists, use that
        if ( val === undefined ) {
            val = curCSS( elem, name, styles );
        }

        //convert "normal" to computed value
        if ( val === "normal" && name in cssNormalTransform ) {
            val = cssNormalTransform[ name ];
        }

        // Return, converting to number if forced or a qualifier was provided and val looks numeric
        if ( extra === "" || extra ) {
            num = parseFloat( val );
            return extra === true || jQuery.isNumeric( num ) ? num || 0 : val;
        }
        return val;
    }
});

curCSS = function( elem, name, _computed ) {
    var width, minWidth, maxWidth,
        computed = _computed || getStyles( elem ),

        // Support: IE9
        // getPropertyValue is only needed for .css('filter') in IE9, see #12537
        ret = computed ? computed.getPropertyValue( name ) || computed[ name ] : undefined,
        style = elem.style;

    if ( computed ) {

        if ( ret === "" && !jQuery.contains( elem.ownerDocument, elem ) ) {
            ret = jQuery.style( elem, name );
        }

        // Support: Safari 5.1
        // A tribute to the "awesome hack by Dean Edwards"
        // Safari 5.1.7 (at least) returns percentage for a larger set of values, but width seems to be reliably pixels
        // this is against the CSSOM draft spec: http://dev.w3.org/csswg/cssom/#resolved-values
        if ( rnumnonpx.test( ret ) && rmargin.test( name ) ) {

            // Remember the original values
            width = style.width;
            minWidth = style.minWidth;
            maxWidth = style.maxWidth;

            // Put in the new values to get a computed value out
            style.minWidth = style.maxWidth = style.width = ret;
            ret = computed.width;

            // Revert the changed values
            style.width = width;
            style.minWidth = minWidth;
            style.maxWidth = maxWidth;
        }
    }

    return ret;
};


function setPositiveNumber( elem, value, subtract ) {
    var matches = rnumsplit.exec( value );
    return matches ?
        // Guard against undefined "subtract", e.g., when used as in cssHooks
        Math.max( 0, matches[ 1 ] - ( subtract || 0 ) ) + ( matches[ 2 ] || "px" ) :
        value;
}

function augmentWidthOrHeight( elem, name, extra, isBorderBox, styles ) {
    var i = extra === ( isBorderBox ? "border" : "content" ) ?
        // If we already have the right measurement, avoid augmentation
        4 :
        // Otherwise initialize for horizontal or vertical properties
        name === "width" ? 1 : 0,

        val = 0;

    for ( ; i < 4; i += 2 ) {
        // both box models exclude margin, so add it if we want it
        if ( extra === "margin" ) {
            val += jQuery.css( elem, extra + cssExpand[ i ], true, styles );
        }

        if ( isBorderBox ) {
            // border-box includes padding, so remove it if we want content
            if ( extra === "content" ) {
                val -= jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );
            }

            // at this point, extra isn't border nor margin, so remove border
            if ( extra !== "margin" ) {
                val -= jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
            }
        } else {
            // at this point, extra isn't content, so add padding
            val += jQuery.css( elem, "padding" + cssExpand[ i ], true, styles );

            // at this point, extra isn't content nor padding, so add border
            if ( extra !== "padding" ) {
                val += jQuery.css( elem, "border" + cssExpand[ i ] + "Width", true, styles );
            }
        }
    }

    return val;
}

function getWidthOrHeight( elem, name, extra ) {

    // Start with offset property, which is equivalent to the border-box value
    var valueIsBorderBox = true,
        val = name === "width" ? elem.offsetWidth : elem.offsetHeight,
        styles = getStyles( elem ),
        isBorderBox = jQuery.support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box";

    // some non-html elements return undefined for offsetWidth, so check for null/undefined
    // svg - https://bugzilla.mozilla.org/show_bug.cgi?id=649285
    // MathML - https://bugzilla.mozilla.org/show_bug.cgi?id=491668
    if ( val <= 0 || val == null ) {
        // Fall back to computed then uncomputed css if necessary
        val = curCSS( elem, name, styles );
        if ( val < 0 || val == null ) {
            val = elem.style[ name ];
        }

        // Computed unit is not pixels. Stop here and return.
        if ( rnumnonpx.test(val) ) {
            return val;
        }

        // we need the check for style in case a browser which returns unreliable values
        // for getComputedStyle silently falls back to the reliable elem.style
        valueIsBorderBox = isBorderBox && ( jQuery.support.boxSizingReliable || val === elem.style[ name ] );

        // Normalize "", auto, and prepare for extra
        val = parseFloat( val ) || 0;
    }

    // use the active box-sizing model to add/subtract irrelevant styles
    return ( val +
        augmentWidthOrHeight(
            elem,
            name,
            extra || ( isBorderBox ? "border" : "content" ),
            valueIsBorderBox,
            styles
        )
    ) + "px";
}

// Try to determine the default display value of an element
function css_defaultDisplay( nodeName ) {
    var doc = document,
        display = elemdisplay[ nodeName ];

    if ( !display ) {
        display = actualDisplay( nodeName, doc );

        // If the simple way fails, read from inside an iframe
        if ( display === "none" || !display ) {
            // Use the already-created iframe if possible
            iframe = ( iframe ||
                jQuery("<iframe frameborder='0' width='0' height='0'/>")
                .css( "cssText", "display:block !important" )
            ).appendTo( doc.documentElement );

            // Always write a new HTML skeleton so Webkit and Firefox don't choke on reuse
            doc = ( iframe[0].contentWindow || iframe[0].contentDocument ).document;
            doc.write("<!doctype html><html><body>");
            doc.close();

            display = actualDisplay( nodeName, doc );
            iframe.detach();
        }

        // Store the correct default display
        elemdisplay[ nodeName ] = display;
    }

    return display;
}

// Called ONLY from within css_defaultDisplay
function actualDisplay( name, doc ) {
    var elem = jQuery( doc.createElement( name ) ).appendTo( doc.body ),
        display = jQuery.css( elem[0], "display" );
    elem.remove();
    return display;
}

jQuery.each([ "height", "width" ], function( i, name ) {
    jQuery.cssHooks[ name ] = {
        get: function( elem, computed, extra ) {
            if ( computed ) {
                // certain elements can have dimension info if we invisibly show them
                // however, it must have a current display style that would benefit from this
                return elem.offsetWidth === 0 && rdisplayswap.test( jQuery.css( elem, "display" ) ) ?
                    jQuery.swap( elem, cssShow, function() {
                        return getWidthOrHeight( elem, name, extra );
                    }) :
                    getWidthOrHeight( elem, name, extra );
            }
        },

        set: function( elem, value, extra ) {
            var styles = extra && getStyles( elem );
            return setPositiveNumber( elem, value, extra ?
                augmentWidthOrHeight(
                    elem,
                    name,
                    extra,
                    jQuery.support.boxSizing && jQuery.css( elem, "boxSizing", false, styles ) === "border-box",
                    styles
                ) : 0
            );
        }
    };
});

// These hooks cannot be added until DOM ready because the support test
// for it is not run until after DOM ready
jQuery(function() {
    // Support: Android 2.3
    if ( !jQuery.support.reliableMarginRight ) {
        jQuery.cssHooks.marginRight = {
            get: function( elem, computed ) {
                if ( computed ) {
                    // Support: Android 2.3
                    // WebKit Bug 13343 - getComputedStyle returns wrong value for margin-right
                    // Work around by temporarily setting element display to inline-block
                    return jQuery.swap( elem, { "display": "inline-block" },
                        curCSS, [ elem, "marginRight" ] );
                }
            }
        };
    }

    // Webkit bug: https://bugs.webkit.org/show_bug.cgi?id=29084
    // getComputedStyle returns percent when specified for top/left/bottom/right
    // rather than make the css module depend on the offset module, we just check for it here
    if ( !jQuery.support.pixelPosition && jQuery.fn.position ) {
        jQuery.each( [ "top", "left" ], function( i, prop ) {
            jQuery.cssHooks[ prop ] = {
                get: function( elem, computed ) {
                    if ( computed ) {
                        computed = curCSS( elem, prop );
                        // if curCSS returns percentage, fallback to offset
                        return rnumnonpx.test( computed ) ?
                            jQuery( elem ).position()[ prop ] + "px" :
                            computed;
                    }
                }
            };
        });
    }

});

if ( jQuery.expr && jQuery.expr.filters ) {
    jQuery.expr.filters.hidden = function( elem ) {
        // Support: Opera <= 12.12
        // Opera reports offsetWidths and offsetHeights less than zero on some elements
        return elem.offsetWidth <= 0 && elem.offsetHeight <= 0;
    };

    jQuery.expr.filters.visible = function( elem ) {
        return !jQuery.expr.filters.hidden( elem );
    };
}

// These hooks are used by animate to expand properties
jQuery.each({
    margin: "",
    padding: "",
    border: "Width"
}, function( prefix, suffix ) {
    jQuery.cssHooks[ prefix + suffix ] = {
        expand: function( value ) {
            var i = 0,
                expanded = {},

                // assumes a single number if not a string
                parts = typeof value === "string" ? value.split(" ") : [ value ];

            for ( ; i < 4; i++ ) {
                expanded[ prefix + cssExpand[ i ] + suffix ] =
                    parts[ i ] || parts[ i - 2 ] || parts[ 0 ];
            }

            return expanded;
        }
    };

    if ( !rmargin.test( prefix ) ) {
        jQuery.cssHooks[ prefix + suffix ].set = setPositiveNumber;
    }
});
var r20 = /%20/g,
    rbracket = /\[\]$/,
    rCRLF = /\r?\n/g,
    rsubmitterTypes = /^(?:submit|button|image|reset|file)$/i,
    rsubmittable = /^(?:input|select|textarea|keygen)/i;

jQuery.fn.extend({
    serialize: function() {
        return jQuery.param( this.serializeArray() );
    },
    serializeArray: function() {
        return this.map(function(){
            // Can add propHook for "elements" to filter or add form elements
            var elements = jQuery.prop( this, "elements" );
            return elements ? jQuery.makeArray( elements ) : this;
        })
        .filter(function(){
            var type = this.type;
            // Use .is(":disabled") so that fieldset[disabled] works
            return this.name && !jQuery( this ).is( ":disabled" ) &&
                rsubmittable.test( this.nodeName ) && !rsubmitterTypes.test( type ) &&
                ( this.checked || !manipulation_rcheckableType.test( type ) );
        })
        .map(function( i, elem ){
            var val = jQuery( this ).val();

            return val == null ?
                null :
                jQuery.isArray( val ) ?
                    jQuery.map( val, function( val ){
                        return { name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
                    }) :
                    { name: elem.name, value: val.replace( rCRLF, "\r\n" ) };
        }).get();
    }
});

//Serialize an array of form elements or a set of
//key/values into a query string
jQuery.param = function( a, traditional ) {
    var prefix,
        s = [],
        add = function( key, value ) {
            // If value is a function, invoke it and return its value
            value = jQuery.isFunction( value ) ? value() : ( value == null ? "" : value );
            s[ s.length ] = encodeURIComponent( key ) + "=" + encodeURIComponent( value );
        };

    // Set traditional to true for jQuery <= 1.3.2 behavior.
    if ( traditional === undefined ) {
        traditional = jQuery.ajaxSettings && jQuery.ajaxSettings.traditional;
    }

    // If an array was passed in, assume that it is an array of form elements.
    if ( jQuery.isArray( a ) || ( a.jquery && !jQuery.isPlainObject( a ) ) ) {
        // Serialize the form elements
        jQuery.each( a, function() {
            add( this.name, this.value );
        });

    } else {
        // If traditional, encode the "old" way (the way 1.3.2 or older
        // did it), otherwise encode params recursively.
        for ( prefix in a ) {
            buildParams( prefix, a[ prefix ], traditional, add );
        }
    }

    // Return the resulting serialization
    return s.join( "&" ).replace( r20, "+" );
};

function buildParams( prefix, obj, traditional, add ) {
    var name;

    if ( jQuery.isArray( obj ) ) {
        // Serialize array item.
        jQuery.each( obj, function( i, v ) {
            if ( traditional || rbracket.test( prefix ) ) {
                // Treat each array item as a scalar.
                add( prefix, v );

            } else {
                // Item is non-scalar (array or object), encode its numeric index.
                buildParams( prefix + "[" + ( typeof v === "object" ? i : "" ) + "]", v, traditional, add );
            }
        });

    } else if ( !traditional && jQuery.type( obj ) === "object" ) {
        // Serialize object item.
        for ( name in obj ) {
            buildParams( prefix + "[" + name + "]", obj[ name ], traditional, add );
        }

    } else {
        // Serialize scalar item.
        add( prefix, obj );
    }
}
jQuery.each( ("blur focus focusin focusout load resize scroll unload click dblclick " +
    "mousedown mouseup mousemove mouseover mouseout mouseenter mouseleave " +
    "change select submit keydown keypress keyup error contextmenu").split(" "), function( i, name ) {

    // Handle event binding
    jQuery.fn[ name ] = function( data, fn ) {
        return arguments.length > 0 ?
            this.on( name, null, data, fn ) :
            this.trigger( name );
    };
});

jQuery.fn.extend({
    hover: function( fnOver, fnOut ) {
        return this.mouseenter( fnOver ).mouseleave( fnOut || fnOver );
    },

    bind: function( types, data, fn ) {
        return this.on( types, null, data, fn );
    },
    unbind: function( types, fn ) {
        return this.off( types, null, fn );
    },

    delegate: function( selector, types, data, fn ) {
        return this.on( types, selector, data, fn );
    },
    undelegate: function( selector, types, fn ) {
        // ( namespace ) or ( selector, types [, fn] )
        return arguments.length === 1 ? this.off( selector, "**" ) : this.off( types, selector || "**", fn );
    }
});
var
    // Document location
    ajaxLocParts,
    ajaxLocation,//location.href

    ajax_nonce = jQuery.now(),

    ajax_rquery = /\?/,
    rhash = /#.*$/,
    rts = /([?&])_=[^&]*/,
    rheaders = /^(.*?):[ \t]*([^\r\n]*)$/mg,
    // #7653, #8125, #8152: local protocol detection
    rlocalProtocol = /^(?:about|app|app-storage|.+-extension|file|res|widget):$/,
    rnoContent = /^(?:GET|HEAD)$/,
    rprotocol = /^\/\//,
    rurl = /^([\w.+-]+:)(?:\/\/([^\/?#:]*)(?::(\d+)|)|)/,

    // Keep a copy of the old load method
    _load = jQuery.fn.load,

    /* Prefilters
     * 1) They are useful to introduce custom dataTypes (see ajax/jsonp.js for an example)
     * 2) These are called:
     *    - BEFORE asking for a transport
     *    - AFTER param serialization (s.data is a string if s.processData is true)
     * 3) key is the dataType
     * 4) the catchall symbol "*" can be used
     * 5) execution will start with transport dataType and THEN continue down to "*" if needed
     */
    prefilters = {},

    /* Transports bindings
     * 1) key is the dataType
     * 2) the catchall symbol "*" can be used
     * 3) selection will start with transport dataType and THEN go to "*" if needed
     */

    transports = {},

    // Avoid comment-prolog char sequence (#10098); must appease lint and evade compression
    allTypes = "*/".concat("*");

// #8138, IE may throw an exception when accessing
// a field from window.location if document.domain has been set
try {
    ajaxLocation = location.href;
} catch( e ) {
    // Use the href attribute of an A element
    // since IE will modify it given document.location
    ajaxLocation = document.createElement( "a" );
    ajaxLocation.href = "";
    ajaxLocation = ajaxLocation.href;
}

// Segment location into parts
ajaxLocParts = rurl.exec( ajaxLocation.toLowerCase() ) || [];

// Base "constructor" for jQuery.ajaxPrefilter and jQuery.ajaxTransport
//前置过滤器和请求分发器,这2个方法是通过私有方法addToPrefiltersOrTransports通过curry手段构造的,分别是保持了prefilters与transports的引用
//可见ajaxPrefilter就维持了addToPrefiltersOrTransports返回函数的引用了,这种就是闭包的手法了,这也是JS的开发人员都需要掌握的好处就是合并多个参数,当然因为维持引用代价就是一点点性能消耗
function addToPrefiltersOrTransports( structure ) {

    // dataTypeExpression is optional and defaults to "*"
    return function( dataTypeExpression, func ) {

        if ( typeof dataTypeExpression !== "string" ) {
            func = dataTypeExpression;
            dataTypeExpression = "*";
        }

        var dataType,
            i = 0,
            dataTypes = dataTypeExpression.toLowerCase().match( core_rnotwhite ) || [];

        if ( jQuery.isFunction( func ) ) {
            // For each dataType in the dataTypeExpression
            while ( (dataType = dataTypes[i++]) ) {
                // Prepend if requested
                if ( dataType[0] === "+" ) {
                    dataType = dataType.slice( 1 ) || "*";
                    (structure[ dataType ] = structure[ dataType ] || []).unshift( func );

                // Otherwise append
                } else {
                    (structure[ dataType ] = structure[ dataType ] || []).push( func );
                }
            }
        }
    };
}

// Base inspection function for prefilters and transports
/*
ajaxPrefilter与ajaxTransport都是通过inspectPrefiltersOrTransports构建器
prefilters中的前置过滤器在请求发送之前、设置请求参数的过程中被调用,调用prefilters的是函数inspectPrefiltersOrTransports;
巧妙的是,transports中的请求分发器在大部分参数设置完成后,也通过函数inspectPrefiltersOrTransports取到与请求类型匹配的请求分发器:
*/
function inspectPrefiltersOrTransports( structure, options, originalOptions, jqXHR ) {

    var inspected = {},
        seekingTransport = ( structure === transports );

    function inspect( dataType ) {
        var selected;
        inspected[ dataType ] = true;
        jQuery.each( structure[ dataType ] || [], function( _, prefilterOrFactory ) {
            var dataTypeOrTransport = prefilterOrFactory( options, originalOptions, jqXHR );
            if( typeof dataTypeOrTransport === "string" && !seekingTransport && !inspected[ dataTypeOrTransport ] ) {
                options.dataTypes.unshift( dataTypeOrTransport );
                inspect( dataTypeOrTransport );
                return false;
            } else if ( seekingTransport ) {
                return !( selected = dataTypeOrTransport );
            }
        });
        return selected;
    }

    return inspect( options.dataTypes[ 0 ] ) || !inspected[ "*" ] && inspect( "*" );
}

// A special extend for ajax options
// that takes "flat" options (not to be deep extended)
// Fixes #9887
function ajaxExtend( target, src ) {
    var key, deep,
        flatOptions = jQuery.ajaxSettings.flatOptions || {};

    for ( key in src ) {
        if ( src[ key ] !== undefined ) {
            ( flatOptions[ key ] ? target : ( deep || (deep = {}) ) )[ key ] = src[ key ];
        }
    }
    if ( deep ) {
        jQuery.extend( true, target, deep );
    }

    return target;
}

jQuery.fn.load = function( url, params, callback ) {
    if ( typeof url !== "string" && _load ) {
        return _load.apply( this, arguments );
    }

    var selector, type, response,
        self = this,
        off = url.indexOf(" ");

    if ( off >= 0 ) {
        selector = url.slice( off );
        url = url.slice( 0, off );
    }

    // If it's a function
    if ( jQuery.isFunction( params ) ) {

        // We assume that it's the callback
        callback = params;
        params = undefined;

    // Otherwise, build a param string
    } else if ( params && typeof params === "object" ) {
        type = "POST";
    }

    // If we have elements to modify, make the request
    if ( self.length > 0 ) {
        jQuery.ajax({
            url: url,

            // if "type" variable is undefined, then "GET" method will be used
            type: type,
            dataType: "html",
            data: params
        }).done(function( responseText ) {

            // Save response for use in complete callback
            response = arguments;

            self.html( selector ?

                // If a selector was specified, locate the right elements in a dummy div
                // Exclude scripts to avoid IE 'Permission Denied' errors
                jQuery("<div>").append( jQuery.parseHTML( responseText ) ).find( selector ) :

                // Otherwise use the full result
                responseText );

        }).complete( callback && function( jqXHR, status ) {
            self.each( callback, response || [ jqXHR.responseText, status, jqXHR ] );
        });
    }

    return this;
};

// Attach a bunch of functions for handling common AJAX events
jQuery.each( [ "ajaxStart", "ajaxStop", "ajaxComplete", "ajaxError", "ajaxSuccess", "ajaxSend" ], function( i, type ){
    jQuery.fn[ type ] = function( fn ){
        return this.on( type, fn );
    };
});

//异步队列deferred   回调队列Callbacks
jQuery.extend({

    // Counter for holding the number of active queries
    active: 0,

    // Last-Modified header cache for next request
    lastModified: {},
    etag: {},

    ajaxSettings: {
        url: ajaxLocation,
        type: "GET",
        isLocal: rlocalProtocol.test( ajaxLocParts[ 1 ] ),
        global: true,//设置是否触发ajaxStart/ajaxStop/ajaxComplete等事件,false是不触发
        processData: true,
        async: true,
        contentType: "application/x-www-form-urlencoded; charset=UTF-8",
        /*
        timeout: 0,
        data: null,
        dataType: null,
        username: null,
        password: null,
        cache: null,
        throws: false,
        traditional: false,
        headers: {},
        */

        accepts: {
            "*": allTypes,
            text: "text/plain",
            html: "text/html",
            xml: "application/xml, text/xml",
            json: "application/json, text/javascript"
        },

        contents: {
            xml: /xml/,
            html: /html/,
            json: /json/
        },

        responseFields: {
            xml: "responseXML",
            text: "responseText",
            json: "responseJSON"
        },

        // Data converters
        // Keys separate source (or catchall "*") and destination types with a single space
        converters: {

            // Convert anything to text
            "* text": String,

            // Text to html (true = no transformation)
            "text html": true,

            // Evaluate text as a json expression
            "text json": jQuery.parseJSON,

            // Parse text as xml
            "text xml": jQuery.parseXML
        },

        // For options that shouldn't be deep extended:
        // you can add your own custom options here if
        // and when you create one that shouldn't be
        // deep extended (see ajaxExtend)
        flatOptions: {
            url: true,
            context: true
        }
    },

    // Creates a full fledged settings object into target
    // with both ajaxSettings and settings fields.
    // If target is omitted, writes into ajaxSettings.
    ajaxSetup: function( target, settings ) {
        return settings ?

            // Building a settings object
            ajaxExtend( ajaxExtend( target, jQuery.ajaxSettings ), settings ) :

            // Extending ajaxSettings
            ajaxExtend( jQuery.ajaxSettings, target );
    },

//预处理的类型取决于由更加接近默认的Content-Type响应,但可以明确使用dataType选项进行设置。如果提供了dataType选项, 响应的Content-Type头信息将被忽略。
    ajaxPrefilter: addToPrefiltersOrTransports( prefilters ),
    ajaxTransport: addToPrefiltersOrTransports( transports ),

    // Main method
    ajax: function( url, options ) {

        // If url is an object, simulate pre-1.5 signature
        if ( typeof url === "object" ) {
            options = url;
            url = undefined;
        }

        // Force options to be an object
        options = options || {};

        var transport,
            // URL without anti-cache param
            cacheURL,
            // Response headers
            responseHeadersString,
            responseHeaders,
            // timeout handle
            timeoutTimer,
            // Cross-domain detection vars
            parts,
            // To know if global events are to be dispatched
            fireGlobals,
            // Loop variable
            i,
            // Create the final options object
            s = jQuery.ajaxSetup( {}, options ),
            // Callbacks context
            callbackContext = s.context || s,
            // Context for global events is callbackContext if it is a DOM node or jQuery collection
            globalEventContext = s.context && ( callbackContext.nodeType || callbackContext.jquery ) ?
                jQuery( callbackContext ) :
                jQuery.event,
            // Deferreds
            deferred = jQuery.Deferred(),
            completeDeferred = jQuery.Callbacks("once memory"),
            // Status-dependent callbacks
            statusCode = s.statusCode || {},
            // Headers (they are sent all at once)
            requestHeaders = {},
            requestHeadersNames = {},
            // The jqXHR state
            state = 0,
            // Default abort message
            strAbort = "canceled",
            // Fake xhr
            //XMLHttpRequest(jqXHR)对象
            jqXHR = {
                readyState: 0,

                // Builds headers hashtable if needed
                getResponseHeader: function( key ) {
                    var match;
                    if ( state === 2 ) {
                        if ( !responseHeaders ) {
                            responseHeaders = {};
                            while ( (match = rheaders.exec( responseHeadersString )) ) {
                                responseHeaders[ match[1].toLowerCase() ] = match[ 2 ];
                            }
                        }
                        match = responseHeaders[ key.toLowerCase() ];
                    }
                    return match == null ? null : match;
                },

                // Raw string
                getAllResponseHeaders: function() {
                    return state === 2 ? responseHeadersString : null;
                },

                // Caches the header
                setRequestHeader: function( name, value ) {
                    var lname = name.toLowerCase();
                    if ( !state ) {
                        name = requestHeadersNames[ lname ] = requestHeadersNames[ lname ] || name;
                        requestHeaders[ name ] = value;
                    }
                    return this;
                },

                // Overrides response content-type header  // 重写相应头content-type
                overrideMimeType: function( type ) {
                    if ( !state ) {
                        s.mimeType = type;
                    }
                    return this;
                },

                // Status-dependent callbacks 对应状态的回调函数集
                statusCode: function( map ) {
                    var code;
                    if ( map ) {
                        if ( state < 2 ) {
                            for ( code in map ) {
                                // Lazy-add the new callback in a way that preserves old ones
                                statusCode[ code ] = [ statusCode[ code ], map[ code ] ];
                            }
                        } else {
                            // Execute the appropriate callbacks // 无论Deferred成功还是失败都执行当前状态回调
                            jqXHR.always( map[ jqXHR.status ] );
                        }
                    }
                    return this;
                },

                // Cancel the request
                abort: function( statusText ) {
                    var finalText = statusText || strAbort;
                    if ( transport ) {
                        transport.abort( finalText );
                    }
                    done( 0, finalText );
                    return this;
                }
            };

        // Attach deferreds
        deferred.promise( jqXHR ).complete = completeDeferred.add;
        //注意这里喔
        jqXHR.success = jqXHR.done;
        jqXHR.error = jqXHR.fail;

        // Remove hash character (#7531: and string promotion)
        // Add protocol if not provided (prefilters might expect it)
        // Handle falsy url in the settings object (#10093: consistency with old signature)
        // We also use the url parameter if available
        s.url = ( ( url || s.url || ajaxLocation ) + "" ).replace( rhash, "" )
            .replace( rprotocol, ajaxLocParts[ 1 ] + "//" );

        // Alias method option to type as per ticket #12004
        s.type = options.method || options.type || s.method || s.type;

        // Extract dataTypes list
        s.dataTypes = jQuery.trim( s.dataType || "*" ).toLowerCase().match( core_rnotwhite ) || [""];

        // A cross-domain request is in order when we have a protocol:host:port mismatch
        if ( s.crossDomain == null ) {
            parts = rurl.exec( s.url.toLowerCase() );
            s.crossDomain = !!( parts &&
                ( parts[ 1 ] !== ajaxLocParts[ 1 ] || parts[ 2 ] !== ajaxLocParts[ 2 ] ||
                    ( parts[ 3 ] || ( parts[ 1 ] === "http:" ? "80" : "443" ) ) !==
                        ( ajaxLocParts[ 3 ] || ( ajaxLocParts[ 1 ] === "http:" ? "80" : "443" ) ) )
            );
        }

        // Convert data if not already a string
        if ( s.data && s.processData && typeof s.data !== "string" ) {
            s.data = jQuery.param( s.data, s.traditional );
        }

        // Apply prefilters
        inspectPrefiltersOrTransports( prefilters, s, options, jqXHR );

        // If request was aborted inside a prefilter, stop there
        if ( state === 2 ) {
            return jqXHR;
        }

        // We can fire global events as of now if asked to
        fireGlobals = s.global;

        // Watch for a new set of requests
        if ( fireGlobals && jQuery.active++ === 0 ) {
            jQuery.event.trigger("ajaxStart");
        }

        // Uppercase the type
        s.type = s.type.toUpperCase();

        // Determine if request has content
        s.hasContent = !rnoContent.test( s.type );

        // Save the URL in case we're toying with the If-Modified-Since
        // and/or If-None-Match header later on
        cacheURL = s.url;

        // More options handling for requests with no content
        if ( !s.hasContent ) {

            // If data is available, append data to url
            if ( s.data ) {
                cacheURL = ( s.url += ( ajax_rquery.test( cacheURL ) ? "&" : "?" ) + s.data );
                // #9682: remove data so that it's not used in an eventual retry
                delete s.data;
            }

            // Add anti-cache in url if needed
            if ( s.cache === false ) {
                s.url = rts.test( cacheURL ) ?

                    // If there is already a '_' parameter, set its value
                    cacheURL.replace( rts, "$1_=" + ajax_nonce++ ) :

                    // Otherwise add one to the end
                    cacheURL + ( ajax_rquery.test( cacheURL ) ? "&" : "?" ) + "_=" + ajax_nonce++;
            }
        }

        // Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
        if ( s.ifModified ) {
            if ( jQuery.lastModified[ cacheURL ] ) {
                jqXHR.setRequestHeader( "If-Modified-Since", jQuery.lastModified[ cacheURL ] );
            }
            if ( jQuery.etag[ cacheURL ] ) {
                jqXHR.setRequestHeader( "If-None-Match", jQuery.etag[ cacheURL ] );
            }
        }

        // Set the correct header, if data is being sent
        if ( s.data && s.hasContent && s.contentType !== false || options.contentType ) {
            jqXHR.setRequestHeader( "Content-Type", s.contentType );
        }

        // Set the Accepts header for the server, depending on the dataType
        jqXHR.setRequestHeader(
            "Accept",
            s.dataTypes[ 0 ] && s.accepts[ s.dataTypes[0] ] ?
                s.accepts[ s.dataTypes[0] ] + ( s.dataTypes[ 0 ] !== "*" ? ", " + allTypes + "; q=0.01" : "" ) :
                s.accepts[ "*" ]
        );

        // Check for headers option
        for ( i in s.headers ) {
            jqXHR.setRequestHeader( i, s.headers[ i ] );
        }

        // Allow custom headers/mimetypes and early abort
        if ( s.beforeSend && ( s.beforeSend.call( callbackContext, jqXHR, s ) === false || state === 2 ) ) {
            // Abort if not done already and return
            return jqXHR.abort();
        }

        // aborting is no longer a cancellation
        strAbort = "abort";

        // Install callbacks on deferreds
        for ( i in { success: 1, error: 1, complete: 1 } ) {
            jqXHR[ i ]( s[ i ] );
        }

        // Get transport
        transport = inspectPrefiltersOrTransports( transports, s, options, jqXHR );

        // If no transport, we auto-abort
        if ( !transport ) {
            done( -1, "No Transport" );
        } else {
            jqXHR.readyState = 1;

            // Send global event
            if ( fireGlobals ) {
                globalEventContext.trigger( "ajaxSend", [ jqXHR, s ] );
            }
            // Timeout
            if ( s.async && s.timeout > 0 ) {
                timeoutTimer = setTimeout(function() {
                    jqXHR.abort("timeout");
                }, s.timeout );
            }

            try {
                state = 1;
                transport.send( requestHeaders, done );
            } catch ( e ) {
                // Propagate exception as error if not done
                if ( state < 2 ) {
                    done( -1, e );
                // Simply rethrow otherwise
                } else {
                    throw e;
                }
            }
        }

        // Callback for when everything is done
        function done( status, nativeStatusText, responses, headers ) {
            var isSuccess, success, error, response, modified,
                statusText = nativeStatusText;

            // Called once
            if ( state === 2 ) {
                return;
            }

            // State is "done" now
            state = 2;

            // Clear timeout if it exists
            if ( timeoutTimer ) {
                clearTimeout( timeoutTimer );
            }

            // Dereference transport for early garbage collection
            // (no matter how long the jqXHR object will be used)
            transport = undefined;

            // Cache response headers
            responseHeadersString = headers || "";

            // Set readyState
            jqXHR.readyState = status > 0 ? 4 : 0;

            // Determine if successful
            isSuccess = status >= 200 && status < 300 || status === 304;

            // Get response data
            if ( responses ) {
                response = ajaxHandleResponses( s, jqXHR, responses );
            }

            // Convert no matter what (that way responseXXX fields are always set)
            response = ajaxConvert( s, response, jqXHR, isSuccess );

            // If successful, handle type chaining
            if ( isSuccess ) {

                // Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
                if ( s.ifModified ) {
                    modified = jqXHR.getResponseHeader("Last-Modified");
                    if ( modified ) {
                        jQuery.lastModified[ cacheURL ] = modified;
                    }
                    modified = jqXHR.getResponseHeader("etag");
                    if ( modified ) {
                        jQuery.etag[ cacheURL ] = modified;
                    }
                }

                // if no content
                if ( status === 204 || s.type === "HEAD" ) {
                    statusText = "nocontent";

                // if not modified
                } else if ( status === 304 ) {
                    statusText = "notmodified";

                // If we have data, let's convert it
                } else {
                    statusText = response.state;
                    success = response.data;
                    error = response.error;
                    isSuccess = !error;
                }
            } else {
                // We extract error from statusText
                // then normalize statusText and status for non-aborts
                error = statusText;
                if ( status || !statusText ) {
                    statusText = "error";
                    if ( status < 0 ) {
                        status = 0;
                    }
                }
            }

            // Set data for the fake xhr object
            jqXHR.status = status;
            jqXHR.statusText = ( nativeStatusText || statusText ) + "";

            // Success/Error
            if ( isSuccess ) {
                deferred.resolveWith( callbackContext, [ success, statusText, jqXHR ] );
            } else {
                deferred.rejectWith( callbackContext, [ jqXHR, statusText, error ] );
            }

            // Status-dependent callbacks
            jqXHR.statusCode( statusCode );
            statusCode = undefined;

            if ( fireGlobals ) {
                globalEventContext.trigger( isSuccess ? "ajaxSuccess" : "ajaxError",
                    [ jqXHR, s, isSuccess ? success : error ] );
            }

            // Complete
            completeDeferred.fireWith( callbackContext, [ jqXHR, statusText ] );

            if ( fireGlobals ) {
                globalEventContext.trigger( "ajaxComplete", [ jqXHR, s ] );
                // Handle the global AJAX counter
                if ( !( --jQuery.active ) ) {
                    jQuery.event.trigger("ajaxStop");
                }
            }
        }

        return jqXHR;
    },

    getJSON: function( url, data, callback ) {
        return jQuery.get( url, data, callback, "json" );
    },

    getScript: function( url, callback ) {//动态异步加载js文件
        /*
        $.getScript('a.js',functio()){};)
        function(){}是回调函数
        */
        return jQuery.get( url, undefined, callback, "script" );
    }
});

jQuery.each( [ "get", "post" ], function( i, method ) {
    jQuery[ method ] = function( url, data, callback, type ) {
        // shift arguments if data argument was omitted
        if ( jQuery.isFunction( data ) ) {
            type = type || callback;
            callback = data;
            data = undefined;
        }

        return jQuery.ajax({
            url: url,
            type: method,
            dataType: type,
            data: data,
            success: callback
        });
    };
});

/* Handles responses to an ajax request:
 * - finds the right dataType (mediates between content-type and expected dataType)
 * - returns the corresponding response
 */
function ajaxHandleResponses( s, jqXHR, responses ) {

    var ct, type, finalDataType, firstDataType,
        contents = s.contents,
        dataTypes = s.dataTypes;

    // Remove auto dataType and get content-type in the process
    while( dataTypes[ 0 ] === "*" ) {
        dataTypes.shift();
        if ( ct === undefined ) {
            ct = s.mimeType || jqXHR.getResponseHeader("Content-Type");
        }
    }

    // Check if we're dealing with a known content-type
    if ( ct ) {
        for ( type in contents ) {
            if ( contents[ type ] && contents[ type ].test( ct ) ) {
                dataTypes.unshift( type );
                break;
            }
        }
    }

    // Check to see if we have a response for the expected dataType
    if ( dataTypes[ 0 ] in responses ) {
        finalDataType = dataTypes[ 0 ];
    } else {
        // Try convertible dataTypes
        for ( type in responses ) {
            if ( !dataTypes[ 0 ] || s.converters[ type + " " + dataTypes[0] ] ) {
                finalDataType = type;
                break;
            }
            if ( !firstDataType ) {
                firstDataType = type;
            }
        }
        // Or just use first one
        finalDataType = finalDataType || firstDataType;
    }

    // If we found a dataType
    // We add the dataType to the list if needed
    // and return the corresponding response
    if ( finalDataType ) {
        if ( finalDataType !== dataTypes[ 0 ] ) {
            dataTypes.unshift( finalDataType );
        }
        return responses[ finalDataType ];
    }
}

/* Chain conversions given the request and the original response
 * Also sets the responseXXX fields on the jqXHR instance
 */
 //类型转换器
function ajaxConvert( s, response, jqXHR, isSuccess ) {
    var conv2, current, conv, tmp, prev,
        converters = {},
        // Work with a copy of dataTypes in case we need to modify it for conversion
        dataTypes = s.dataTypes.slice();

    // Create converters map with lowercased keys
    if ( dataTypes[ 1 ] ) {
        for ( conv in s.converters ) {
            converters[ conv.toLowerCase() ] = s.converters[ conv ];
        }
    }

    current = dataTypes.shift();

    // Convert to each sequential dataType
    while ( current ) {

        if ( s.responseFields[ current ] ) {
            jqXHR[ s.responseFields[ current ] ] = response;
        }

        // Apply the dataFilter if provided
        if ( !prev && isSuccess && s.dataFilter ) {
            response = s.dataFilter( response, s.dataType );
        }

        prev = current;
        current = dataTypes.shift();

        if ( current ) {

        // There's only work to do if current dataType is non-auto
            if ( current === "*" ) {

                current = prev;

            // Convert response if prev dataType is non-auto and differs from current
            } else if ( prev !== "*" && prev !== current ) {

                // Seek a direct converter
                conv = converters[ prev + " " + current ] || converters[ "* " + current ];

                // If none found, seek a pair
                if ( !conv ) {
                    for ( conv2 in converters ) {

                        // If conv2 outputs current
                        tmp = conv2.split( " " );
                        if ( tmp[ 1 ] === current ) {

                            // If prev can be converted to accepted input
                            conv = converters[ prev + " " + tmp[ 0 ] ] ||
                                converters[ "* " + tmp[ 0 ] ];
                            if ( conv ) {
                                // Condense equivalence converters
                                if ( conv === true ) {
                                    conv = converters[ conv2 ];

                                // Otherwise, insert the intermediate dataType
                                } else if ( converters[ conv2 ] !== true ) {
                                    current = tmp[ 0 ];
                                    dataTypes.unshift( tmp[ 1 ] );
                                }
                                break;
                            }
                        }
                    }
                }

                // Apply converter (if not an equivalence)
                if ( conv !== true ) {

                    // Unless errors are allowed to bubble, catch and return them
                    if ( conv && s[ "throws" ] ) {
                        response = conv( response );
                    } else {
                        try {
                            response = conv( response );
                        } catch ( e ) {
                            return { state: "parsererror", error: conv ? e : "No conversion from " + prev + " to " + current };
                        }
                    }
                }
            }
        }
    }

    return { state: "success", data: response };
}
// Install script dataType
jQuery.ajaxSetup({
    accepts: {
        script: "text/javascript, application/javascript, application/ecmascript, application/x-ecmascript"
    },
    contents: {
        script: /(?:java|ecma)script/
    },
    converters: {
        "text script": function( text ) {
            jQuery.globalEval( text );
            return text;
        }
    }
});

// Handle cache's special case and crossDomain
jQuery.ajaxPrefilter( "script", function( s ) {
    if ( s.cache === undefined ) {
        s.cache = false;
    }
    if ( s.crossDomain ) {
        s.type = "GET";
    }
});

// Bind script tag hack transport
//请求分发器  请求分发器顾名思义发送请求,那么底层的ajax发送请求是通过send方法
jQuery.ajaxTransport( "script", function( s ) {
    // This transport only deals with cross domain requests
    if ( s.crossDomain ) {
        var script, callback;
        return {
            send: function( _, complete ) {
                script = jQuery("<script>").prop({
                    async: true,
                    charset: s.scriptCharset,
                    src: s.url
                }).on(
                    "load error",
                    callback = function( evt ) {
                        script.remove();
                        callback = null;
                        if ( evt ) {
                            complete( evt.type === "error" ? 404 : 200, evt.type );
                        }
                    }
                );
                document.head.appendChild( script[ 0 ] );
            },
            abort: function() {
                if ( callback ) {
                    callback();
                }
            }
        };
    }
});
var oldCallbacks = [],
    rjsonp = /(=)\?(?=&|$)|\?\?/;

// Default jsonp settings
jQuery.ajaxSetup({
    jsonp: "callback",
    jsonpCallback: function() {
        var callback = oldCallbacks.pop() || ( jQuery.expando + "_" + ( ajax_nonce++ ) );
        this[ callback ] = true;
        return callback;
    }
});

// Detect, normalize options and install callbacks for jsonp requests
//前置过滤器
jQuery.ajaxPrefilter( "json jsonp", function( s, originalSettings, jqXHR ) {

    var callbackName, overwritten, responseContainer,
        jsonProp = s.jsonp !== false && ( rjsonp.test( s.url ) ?
            "url" :
            typeof s.data === "string" && !( s.contentType || "" ).indexOf("application/x-www-form-urlencoded") && rjsonp.test( s.data ) && "data"
        );

    // Handle iff the expected data type is "jsonp" or we have a parameter to set
    if ( jsonProp || s.dataTypes[ 0 ] === "jsonp" ) {

        // Get callback name, remembering preexisting value associated with it
        //jsonpCallback为jsonp请求指定一个回调函数名。这个值将用来取代jQuery自动生成的随机函数名。这主要用来让jQuery生成一个独特的函数名,这样管理请求更容易,也能方便地提供回调函数和错误处理。你也可以在想让浏览器缓存GET请求的时候,指定这个回调函数名。从jQuery 1.5开始,你也可以使用一个函数作为该参数设置,在这种情况下,该函数的返回值就是jsonpCallback的结果。
        //在一个jsonp请求中重写回调函数的名字。这个值用来替代在"callback=?"这种GET或POST请求中URL参数里的"callback"部分,比如{jsonp:'onJsonPLoad'}会导致将"onJsonPLoad=?"传给服务器。在jQuery 1.5,,设置jsonp选项为false,阻止了jQuery从加入"?callback"字符串的URL或试图使用"=?"转换。在这种情况下,你也应该明确设置jsonpCallback设置。例如, { jsonp: false, jsonpCallback: "callbackName" }、
        callbackName = s.jsonpCallback = jQuery.isFunction( s.jsonpCallback ) ?
            s.jsonpCallback() :
            s.jsonpCallback;

        // Insert callback into url or form data
        if ( jsonProp ) {
            s[ jsonProp ] = s[ jsonProp ].replace( rjsonp, "$1" + callbackName );
        } else if ( s.jsonp !== false ) {
            s.url += ( ajax_rquery.test( s.url ) ? "&" : "?" ) + s.jsonp + "=" + callbackName;
        }

        // Use data converter to retrieve json after script execution
        s.converters["script json"] = function() {
            if ( !responseContainer ) {
                jQuery.error( callbackName + " was not called" );
            }
            return responseContainer[ 0 ];
        };

        // force json dataType
        s.dataTypes[ 0 ] = "json";

        // Install callback
        overwritten = window[ callbackName ];
        window[ callbackName ] = function() {
            responseContainer = arguments;
        };

        // Clean-up function (fires after converters)
        jqXHR.always(function() {
            // Restore preexisting value
            window[ callbackName ] = overwritten;

            // Save back as free
            if ( s[ callbackName ] ) {
                // make sure that re-using the options doesn't screw things around
                s.jsonpCallback = originalSettings.jsonpCallback;

                // save the callback name for future use
                oldCallbacks.push( callbackName );
            }

            // Call if it was a function and we have a response
            if ( responseContainer && jQuery.isFunction( overwritten ) ) {
                overwritten( responseContainer[ 0 ] );
            }

            responseContainer = overwritten = undefined;
        });

        // Delegate to script
        return "script";
    }
});
jQuery.ajaxSettings.xhr = function() {
    try {
        return new XMLHttpRequest();
    } catch( e ) {}
};

var xhrSupported = jQuery.ajaxSettings.xhr(),
    xhrSuccessStatus = {
        // file protocol always yields status code 0, assume 200
        0: 200,
        // Support: IE9
        // #1450: sometimes IE returns 1223 when it should be 204
        1223: 204
    },
    // Support: IE9
    // We need to keep track of outbound xhr and abort them manually
    // because IE is not smart enough to do it all by itself
    xhrId = 0,
    xhrCallbacks = {};

if ( window.ActiveXObject ) {
    jQuery( window ).on( "unload", function() {
        for( var key in xhrCallbacks ) {
            xhrCallbacks[ key ]();
        }
        xhrCallbacks = undefined;
    });
}
//withCredentials是ajax跨域的一个属性xhrSupported就是xmlhttpRequest对象,,cors就是判断ajax是否支持跨域
jQuery.support.cors = !!xhrSupported && ( "withCredentials" in xhrSupported );
jQuery.support.ajax = xhrSupported = !!xhrSupported;

jQuery.ajaxTransport(function( options ) {
    var callback;
    // Cross domain only allowed if supported through XMLHttpRequest
    if ( jQuery.support.cors || xhrSupported && !options.crossDomain ) {
        return {
            send: function( headers, complete ) {
                var i, id,
                    xhr = options.xhr();
                xhr.open( options.type, options.url, options.async, options.username, options.password );
                // Apply custom fields if provided
                if ( options.xhrFields ) {
                    for ( i in options.xhrFields ) {
                        xhr[ i ] = options.xhrFields[ i ];
                    }
                }
                // Override mime type if needed
                if ( options.mimeType && xhr.overrideMimeType ) {
                    xhr.overrideMimeType( options.mimeType );
                }
                // X-Requested-With header
                // For cross-domain requests, seeing as conditions for a preflight are
                // akin to a jigsaw puzzle, we simply never set it to be sure.
                // (it can always be set on a per-request basis or even using ajaxSetup)
                // For same-domain requests, won't change header if already provided.
                if ( !options.crossDomain && !headers["X-Requested-With"] ) {
                    headers["X-Requested-With"] = "XMLHttpRequest";
                }
                // Set headers
                for ( i in headers ) {
                    xhr.setRequestHeader( i, headers[ i ] );
                }
                // Callback
                callback = function( type ) {
                    return function() {
                        if ( callback ) {
                            delete xhrCallbacks[ id ];
                            callback = xhr.onload = xhr.onerror = null;
                            if ( type === "abort" ) {
                                xhr.abort();
                            } else if ( type === "error" ) {
                                complete(
                                    // file protocol always yields status 0, assume 404
                                    xhr.status || 404,
                                    xhr.statusText
                                );
                            } else {
                                complete(
                                    xhrSuccessStatus[ xhr.status ] || xhr.status,
                                    xhr.statusText,
                                    // Support: IE9
                                    // #11426: When requesting binary data, IE9 will throw an exception
                                    // on any attempt to access responseText
                                    typeof xhr.responseText === "string" ? {
                                        text: xhr.responseText
                                    } : undefined,
                                    xhr.getAllResponseHeaders()
                                );
                            }
                        }
                    };
                };
                // Listen to events
                xhr.onload = callback();
                xhr.onerror = callback("error");
                // Create the abort callback
                callback = xhrCallbacks[( id = xhrId++ )] = callback("abort");
                // Do send the request
                // This may raise an exception which is actually
                // handled in jQuery.ajax (so no try/catch here)
                xhr.send( options.hasContent && options.data || null );
            },
            abort: function() {
                if ( callback ) {
                    callback();
                }
            }
        };
    }
});


var fxNow, timerId,
    rfxtypes = /^(?:toggle|show|hide)$/,
    rfxnum = new RegExp( "^(?:([+-])=|)(" + core_pnum + ")([a-z%]*)$", "i" ),
    rrun = /queueHooks$/,
    animationPrefilters = [ defaultPrefilter ],
    tweeners = {
        "*": [function( prop, value ) {
            var tween = this.createTween( prop, value ),
                target = tween.cur(),
                parts = rfxnum.exec( value ),
                unit = parts && parts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),

                // Starting value computation is required for potential unit mismatches
                start = ( jQuery.cssNumber[ prop ] || unit !== "px" && +target ) &&
                    rfxnum.exec( jQuery.css( tween.elem, prop ) ),
                scale = 1,
                maxIterations = 20;

            if ( start && start[ 3 ] !== unit ) {
                // Trust units reported by jQuery.css
                unit = unit || start[ 3 ];

                // Make sure we update the tween properties later on
                parts = parts || [];

                // Iteratively approximate from a nonzero starting point
                start = +target || 1;

                do {
                    // If previous iteration zeroed out, double until we get *something*
                    // Use a string for doubling factor so we don't accidentally see scale as unchanged below
                    scale = scale || ".5";

                    // Adjust and apply
                    start = start / scale;
                    jQuery.style( tween.elem, prop, start + unit );

                // Update scale, tolerating zero or NaN from tween.cur()
                // And breaking the loop if scale is unchanged or perfect, or if we've just had enough
                } while ( scale !== (scale = tween.cur() / target) && scale !== 1 && --maxIterations );
            }

            // Update tween properties
            if ( parts ) {
                start = tween.start = +start || +target || 0;
                tween.unit = unit;
                // If a +=/-= token was provided, we're doing a relative animation
                tween.end = parts[ 1 ] ?
                    start + ( parts[ 1 ] + 1 ) * parts[ 2 ] :
                    +parts[ 2 ];
            }

            return tween;
        }]
    };

// Animations created synchronously will run synchronously
function createFxNow() {
    setTimeout(function() {
        fxNow = undefined;
    });
    return ( fxNow = jQuery.now() );
}

function createTween( value, prop, animation ) {
    var tween,
        collection = ( tweeners[ prop ] || [] ).concat( tweeners[ "*" ] ),
        index = 0,
        length = collection.length;
    for ( ; index < length; index++ ) {
        if ( (tween = collection[ index ].call( animation, prop, value )) ) {

            // we're done with this property
            return tween;
        }
    }
}

function Animation( elem, properties, options ) {
    var result,
        stopped,
        index = 0,
        length = animationPrefilters.length,
        deferred = jQuery.Deferred().always( function() {
            // don't match elem in the :animated selector
            delete tick.elem;
        }),
        tick = function() {
            if ( stopped ) {
                return false;
            }
            var currentTime = fxNow || createFxNow(),
                remaining = Math.max( 0, animation.startTime + animation.duration - currentTime ),
                // archaic crash bug won't allow us to use 1 - ( 0.5 || 0 ) (#12497)
                temp = remaining / animation.duration || 0,
                percent = 1 - temp,
                index = 0,
                length = animation.tweens.length;

            for ( ; index < length ; index++ ) {
                animation.tweens[ index ].run( percent );
            }

            deferred.notifyWith( elem, [ animation, percent, remaining ]);

            if ( percent < 1 && length ) {
                return remaining;
            } else {
                deferred.resolveWith( elem, [ animation ] );
                return false;
            }
        },
        animation = deferred.promise({
            elem: elem,
            props: jQuery.extend( {}, properties ),
            opts: jQuery.extend( true, { specialEasing: {} }, options ),
            originalProperties: properties,
            originalOptions: options,
            startTime: fxNow || createFxNow(),
            duration: options.duration,
            tweens: [],
            createTween: function( prop, end ) {
                var tween = jQuery.Tween( elem, animation.opts, prop, end,
                        animation.opts.specialEasing[ prop ] || animation.opts.easing );
                animation.tweens.push( tween );
                return tween;
            },
            stop: function( gotoEnd ) {
                var index = 0,
                    // if we are going to the end, we want to run all the tweens
                    // otherwise we skip this part
                    length = gotoEnd ? animation.tweens.length : 0;
                if ( stopped ) {
                    return this;
                }
                stopped = true;
                for ( ; index < length ; index++ ) {
                    animation.tweens[ index ].run( 1 );
                }

                // resolve when we played the last frame
                // otherwise, reject
                if ( gotoEnd ) {
                    deferred.resolveWith( elem, [ animation, gotoEnd ] );
                } else {
                    deferred.rejectWith( elem, [ animation, gotoEnd ] );
                }
                return this;
            }
        }),
        props = animation.props;

    propFilter( props, animation.opts.specialEasing );

    for ( ; index < length ; index++ ) {
        result = animationPrefilters[ index ].call( animation, elem, props, animation.opts );
        if ( result ) {
            return result;
        }
    }

    jQuery.map( props, createTween, animation );

    if ( jQuery.isFunction( animation.opts.start ) ) {
        animation.opts.start.call( elem, animation );
    }

    jQuery.fx.timer(
        jQuery.extend( tick, {
            elem: elem,
            anim: animation,
            queue: animation.opts.queue
        })
    );

    // attach callbacks from options
    return animation.progress( animation.opts.progress )
        .done( animation.opts.done, animation.opts.complete )
        .fail( animation.opts.fail )
        .always( animation.opts.always );
}

function propFilter( props, specialEasing ) {
    var index, name, easing, value, hooks;

    // camelCase, specialEasing and expand cssHook pass
    for ( index in props ) {
        name = jQuery.camelCase( index );
        easing = specialEasing[ name ];
        value = props[ index ];
        if ( jQuery.isArray( value ) ) {
            easing = value[ 1 ];
            value = props[ index ] = value[ 0 ];
        }

        if ( index !== name ) {
            props[ name ] = value;
            delete props[ index ];
        }

        hooks = jQuery.cssHooks[ name ];
        if ( hooks && "expand" in hooks ) {
            value = hooks.expand( value );
            delete props[ name ];

            // not quite $.extend, this wont overwrite keys already present.
            // also - reusing 'index' from above because we have the correct "name"
            for ( index in value ) {
                if ( !( index in props ) ) {
                    props[ index ] = value[ index ];
                    specialEasing[ index ] = easing;
                }
            }
        } else {
            specialEasing[ name ] = easing;
        }
    }
}

jQuery.Animation = jQuery.extend( Animation, {

    tweener: function( props, callback ) {
        if ( jQuery.isFunction( props ) ) {
            callback = props;
            props = [ "*" ];
        } else {
            props = props.split(" ");
        }

        var prop,
            index = 0,
            length = props.length;

        for ( ; index < length ; index++ ) {
            prop = props[ index ];
            tweeners[ prop ] = tweeners[ prop ] || [];
            tweeners[ prop ].unshift( callback );
        }
    },

    prefilter: function( callback, prepend ) {
        if ( prepend ) {
            animationPrefilters.unshift( callback );
        } else {
            animationPrefilters.push( callback );
        }
    }
});

function defaultPrefilter( elem, props, opts ) {
    /* jshint validthis: true */
    var prop, value, toggle, tween, hooks, oldfire,
        anim = this,
        orig = {},
        style = elem.style,
        hidden = elem.nodeType && isHidden( elem ),
        dataShow = data_priv.get( elem, "fxshow" );

    // handle queue: false promises
    if ( !opts.queue ) {
        hooks = jQuery._queueHooks( elem, "fx" );
        if ( hooks.unqueued == null ) {
            hooks.unqueued = 0;
            oldfire = hooks.empty.fire;
            hooks.empty.fire = function() {
                if ( !hooks.unqueued ) {
                    oldfire();
                }
            };
        }
        hooks.unqueued++;

        anim.always(function() {
            // doing this makes sure that the complete handler will be called
            // before this completes
            anim.always(function() {
                hooks.unqueued--;
                if ( !jQuery.queue( elem, "fx" ).length ) {
                    hooks.empty.fire();
                }
            });
        });
    }

    // height/width overflow pass
    if ( elem.nodeType === 1 && ( "height" in props || "width" in props ) ) {
        // Make sure that nothing sneaks out
        // Record all 3 overflow attributes because IE9-10 do not
        // change the overflow attribute when overflowX and
        // overflowY are set to the same value
        opts.overflow = [ style.overflow, style.overflowX, style.overflowY ];

        // Set display property to inline-block for height/width
        // animations on inline elements that are having width/height animated
        if ( jQuery.css( elem, "display" ) === "inline" &&
                jQuery.css( elem, "float" ) === "none" ) {

            style.display = "inline-block";
        }
    }

    if ( opts.overflow ) {
        style.overflow = "hidden";
        anim.always(function() {
            style.overflow = opts.overflow[ 0 ];
            style.overflowX = opts.overflow[ 1 ];
            style.overflowY = opts.overflow[ 2 ];
        });
    }


    // show/hide pass
    for ( prop in props ) {
        value = props[ prop ];
        if ( rfxtypes.exec( value ) ) {
            delete props[ prop ];
            toggle = toggle || value === "toggle";
            if ( value === ( hidden ? "hide" : "show" ) ) {

                // If there is dataShow left over from a stopped hide or show and we are going to proceed with show, we should pretend to be hidden
                if ( value === "show" && dataShow && dataShow[ prop ] !== undefined ) {
                    hidden = true;
                } else {
                    continue;
                }
            }
            orig[ prop ] = dataShow && dataShow[ prop ] || jQuery.style( elem, prop );
        }
    }

    if ( !jQuery.isEmptyObject( orig ) ) {
        if ( dataShow ) {
            if ( "hidden" in dataShow ) {
                hidden = dataShow.hidden;
            }
        } else {
            dataShow = data_priv.access( elem, "fxshow", {} );
        }

        // store state if its toggle - enables .stop().toggle() to "reverse"
        if ( toggle ) {
            dataShow.hidden = !hidden;
        }
        if ( hidden ) {
            jQuery( elem ).show();
        } else {
            anim.done(function() {
                jQuery( elem ).hide();
            });
        }
        anim.done(function() {
            var prop;

            data_priv.remove( elem, "fxshow" );
            for ( prop in orig ) {
                jQuery.style( elem, prop, orig[ prop ] );
            }
        });
        for ( prop in orig ) {
            tween = createTween( hidden ? dataShow[ prop ] : 0, prop, anim );

            if ( !( prop in dataShow ) ) {
                dataShow[ prop ] = tween.start;
                if ( hidden ) {
                    tween.end = tween.start;
                    tween.start = prop === "width" || prop === "height" ? 1 : 0;
                }
            }
        }
    }
}

function Tween( elem, options, prop, end, easing ) {
    return new Tween.prototype.init( elem, options, prop, end, easing );
}
jQuery.Tween = Tween;

Tween.prototype = {
    constructor: Tween,
    init: function( elem, options, prop, end, easing, unit ) {
        this.elem = elem;
        this.prop = prop;
        this.easing = easing || "swing";
        this.options = options;
        this.start = this.now = this.cur();
        this.end = end;
        this.unit = unit || ( jQuery.cssNumber[ prop ] ? "" : "px" );
    },
    cur: function() {
        var hooks = Tween.propHooks[ this.prop ];

        return hooks && hooks.get ?
            hooks.get( this ) :
            Tween.propHooks._default.get( this );
    },
    run: function( percent ) {
        var eased,
            hooks = Tween.propHooks[ this.prop ];

        if ( this.options.duration ) {
            this.pos = eased = jQuery.easing[ this.easing ](
                percent, this.options.duration * percent, 0, 1, this.options.duration
            );
        } else {
            this.pos = eased = percent;
        }
        this.now = ( this.end - this.start ) * eased + this.start;

        if ( this.options.step ) {
            this.options.step.call( this.elem, this.now, this );
        }

        if ( hooks && hooks.set ) {
            hooks.set( this );
        } else {
            Tween.propHooks._default.set( this );
        }
        return this;
    }
};

Tween.prototype.init.prototype = Tween.prototype;

Tween.propHooks = {
    _default: {
        get: function( tween ) {
            var result;

            if ( tween.elem[ tween.prop ] != null &&
                (!tween.elem.style || tween.elem.style[ tween.prop ] == null) ) {
                return tween.elem[ tween.prop ];
            }

            // passing an empty string as a 3rd parameter to .css will automatically
            // attempt a parseFloat and fallback to a string if the parse fails
            // so, simple values such as "10px" are parsed to Float.
            // complex values such as "rotate(1rad)" are returned as is.
            result = jQuery.css( tween.elem, tween.prop, "" );
            // Empty strings, null, undefined and "auto" are converted to 0.
            return !result || result === "auto" ? 0 : result;
        },
        set: function( tween ) {
            // use step hook for back compat - use cssHook if its there - use .style if its
            // available and use plain properties where available
            if ( jQuery.fx.step[ tween.prop ] ) {
                jQuery.fx.step[ tween.prop ]( tween );
            } else if ( tween.elem.style && ( tween.elem.style[ jQuery.cssProps[ tween.prop ] ] != null || jQuery.cssHooks[ tween.prop ] ) ) {
                jQuery.style( tween.elem, tween.prop, tween.now + tween.unit );
            } else {
                tween.elem[ tween.prop ] = tween.now;
            }
        }
    }
};

// Support: IE9
// Panic based approach to setting things on disconnected nodes

Tween.propHooks.scrollTop = Tween.propHooks.scrollLeft = {
    set: function( tween ) {
        if ( tween.elem.nodeType && tween.elem.parentNode ) {
            tween.elem[ tween.prop ] = tween.now;
        }
    }
};

jQuery.each([ "toggle", "show", "hide" ], function( i, name ) {
    var cssFn = jQuery.fn[ name ];
    jQuery.fn[ name ] = function( speed, easing, callback ) {
        return speed == null || typeof speed === "boolean" ?
            cssFn.apply( this, arguments ) :
            this.animate( genFx( name, true ), speed, easing, callback );
    };
});

jQuery.fn.extend({
    fadeTo: function( speed, to, easing, callback ) {

        // show any hidden elements after setting opacity to 0
        return this.filter( isHidden ).css( "opacity", 0 ).show()

            // animate to the value specified
            .end().animate({ opacity: to }, speed, easing, callback );
    },
    animate: function( prop, speed, easing, callback ) {
        var empty = jQuery.isEmptyObject( prop ),
            optall = jQuery.speed( speed, easing, callback ),
            doAnimation = function() {
                // Operate on a copy of prop so per-property easing won't be lost
                var anim = Animation( this, jQuery.extend( {}, prop ), optall );

                // Empty animations, or finishing resolves immediately
                if ( empty || data_priv.get( this, "finish" ) ) {
                    anim.stop( true );
                }
            };
            doAnimation.finish = doAnimation;

        return empty || optall.queue === false ?
            this.each( doAnimation ) :
            this.queue( optall.queue, doAnimation );
    },
    stop: function( type, clearQueue, gotoEnd ) {
        var stopQueue = function( hooks ) {
            var stop = hooks.stop;
            delete hooks.stop;
            stop( gotoEnd );
        };

        if ( typeof type !== "string" ) {
            gotoEnd = clearQueue;
            clearQueue = type;
            type = undefined;
        }
        if ( clearQueue && type !== false ) {
            this.queue( type || "fx", [] );
        }

        return this.each(function() {
            var dequeue = true,
                index = type != null && type + "queueHooks",
                timers = jQuery.timers,
                data = data_priv.get( this );

            if ( index ) {
                if ( data[ index ] && data[ index ].stop ) {
                    stopQueue( data[ index ] );
                }
            } else {
                for ( index in data ) {
                    if ( data[ index ] && data[ index ].stop && rrun.test( index ) ) {
                        stopQueue( data[ index ] );
                    }
                }
            }

            for ( index = timers.length; index--; ) {
                if ( timers[ index ].elem === this && (type == null || timers[ index ].queue === type) ) {
                    timers[ index ].anim.stop( gotoEnd );
                    dequeue = false;
                    timers.splice( index, 1 );
                }
            }

            // start the next in the queue if the last step wasn't forced
            // timers currently will call their complete callbacks, which will dequeue
            // but only if they were gotoEnd
            if ( dequeue || !gotoEnd ) {
                jQuery.dequeue( this, type );
            }
        });
    },
    finish: function( type ) {
        if ( type !== false ) {
            type = type || "fx";
        }
        return this.each(function() {
            var index,
                data = data_priv.get( this ),
                queue = data[ type + "queue" ],
                hooks = data[ type + "queueHooks" ],
                timers = jQuery.timers,
                length = queue ? queue.length : 0;

            // enable finishing flag on private data
            data.finish = true;

            // empty the queue first
            jQuery.queue( this, type, [] );

            if ( hooks && hooks.stop ) {
                hooks.stop.call( this, true );
            }

            // look for any active animations, and finish them
            for ( index = timers.length; index--; ) {
                if ( timers[ index ].elem === this && timers[ index ].queue === type ) {
                    timers[ index ].anim.stop( true );
                    timers.splice( index, 1 );
                }
            }

            // look for any animations in the old queue and finish them
            for ( index = 0; index < length; index++ ) {
                if ( queue[ index ] && queue[ index ].finish ) {
                    queue[ index ].finish.call( this );
                }
            }

            // turn off finishing flag
            delete data.finish;
        });
    }
});

// Generate parameters to create a standard animation
function genFx( type, includeWidth ) {
    var which,
        attrs = { height: type },
        i = 0;

    // if we include width, step value is 1 to do all cssExpand values,
    // if we don't include width, step value is 2 to skip over Left and Right
    includeWidth = includeWidth? 1 : 0;
    for( ; i < 4 ; i += 2 - includeWidth ) {
        which = cssExpand[ i ];
        attrs[ "margin" + which ] = attrs[ "padding" + which ] = type;
    }

    if ( includeWidth ) {
        attrs.opacity = attrs.width = type;
    }

    return attrs;
}

// Generate shortcuts for custom animations
jQuery.each({
    slideDown: genFx("show"),
    slideUp: genFx("hide"),
    slideToggle: genFx("toggle"),
    fadeIn: { opacity: "show" },
    fadeOut: { opacity: "hide" },
    fadeToggle: { opacity: "toggle" }
}, function( name, props ) {
    jQuery.fn[ name ] = function( speed, easing, callback ) {
        return this.animate( props, speed, easing, callback );
    };
});

jQuery.speed = function( speed, easing, fn ) {
    var opt = speed && typeof speed === "object" ? jQuery.extend( {}, speed ) : {
        complete: fn || !fn && easing ||
            jQuery.isFunction( speed ) && speed,
        duration: speed,
        easing: fn && easing || easing && !jQuery.isFunction( easing ) && easing
    };

    opt.duration = jQuery.fx.off ? 0 : typeof opt.duration === "number" ? opt.duration :
        opt.duration in jQuery.fx.speeds ? jQuery.fx.speeds[ opt.duration ] : jQuery.fx.speeds._default;

    // normalize opt.queue - true/undefined/null -> "fx"
    if ( opt.queue == null || opt.queue === true ) {
        opt.queue = "fx";
    }

    // Queueing
    opt.old = opt.complete;

    opt.complete = function() {
        if ( jQuery.isFunction( opt.old ) ) {
            opt.old.call( this );
        }

        if ( opt.queue ) {
            jQuery.dequeue( this, opt.queue );
        }
    };

    return opt;
};

jQuery.easing = {
    linear: function( p ) {
        return p;
    },
    swing: function( p ) {
        return 0.5 - Math.cos( p*Math.PI ) / 2;
    }
};

jQuery.timers = [];
jQuery.fx = Tween.prototype.init;
jQuery.fx.tick = function() {
    var timer,
        timers = jQuery.timers,
        i = 0;

    fxNow = jQuery.now();

    for ( ; i < timers.length; i++ ) {
        timer = timers[ i ];
        // Checks the timer has not already been removed
        if ( !timer() && timers[ i ] === timer ) {
            timers.splice( i--, 1 );
        }
    }

    if ( !timers.length ) {
        jQuery.fx.stop();
    }
    fxNow = undefined;
};

jQuery.fx.timer = function( timer ) {
    if ( timer() && jQuery.timers.push( timer ) ) {
        jQuery.fx.start();
    }
};

jQuery.fx.interval = 13;

jQuery.fx.start = function() {
    if ( !timerId ) {
        timerId = setInterval( jQuery.fx.tick, jQuery.fx.interval );
    }
};

jQuery.fx.stop = function() {
    clearInterval( timerId );
    timerId = null;
};

jQuery.fx.speeds = {
    slow: 600,
    fast: 200,
    // Default speed
    _default: 400
};

// Back Compat <1.8 extension point
jQuery.fx.step = {};

if ( jQuery.expr && jQuery.expr.filters ) {
    jQuery.expr.filters.animated = function( elem ) {
        return jQuery.grep(jQuery.timers, function( fn ) {
            return elem === fn.elem;
        }).length;
    };
}
jQuery.fn.offset = function( options ) {
    if ( arguments.length ) {
        return options === undefined ?
            this :
            this.each(function( i ) {
                jQuery.offset.setOffset( this, options, i );
            });
    }

    var docElem, win,
        elem = this[ 0 ],
        box = { top: 0, left: 0 },
        doc = elem && elem.ownerDocument;

    if ( !doc ) {
        return;
    }

    docElem = doc.documentElement;

    // Make sure it's not a disconnected DOM node
    if ( !jQuery.contains( docElem, elem ) ) {
        return box;
    }

    // If we don't have gBCR, just use 0,0 rather than error
    // BlackBerry 5, iOS 3 (original iPhone)
    if ( typeof elem.getBoundingClientRect !== core_strundefined ) {
        box = elem.getBoundingClientRect();
    }
    win = getWindow( doc );
    return {
        top: box.top + win.pageYOffset - docElem.clientTop,
        left: box.left + win.pageXOffset - docElem.clientLeft
    };
};

jQuery.offset = {

    setOffset: function( elem, options, i ) {
        var curPosition, curLeft, curCSSTop, curTop, curOffset, curCSSLeft, calculatePosition,
            position = jQuery.css( elem, "position" ),
            curElem = jQuery( elem ),
            props = {};

        // Set position first, in-case top/left are set even on static elem
        if ( position === "static" ) {
            elem.style.position = "relative";
        }

        curOffset = curElem.offset();
        curCSSTop = jQuery.css( elem, "top" );
        curCSSLeft = jQuery.css( elem, "left" );
        calculatePosition = ( position === "absolute" || position === "fixed" ) && ( curCSSTop + curCSSLeft ).indexOf("auto") > -1;

        // Need to be able to calculate position if either top or left is auto and position is either absolute or fixed
        if ( calculatePosition ) {
            curPosition = curElem.position();
            curTop = curPosition.top;
            curLeft = curPosition.left;

        } else {
            curTop = parseFloat( curCSSTop ) || 0;
            curLeft = parseFloat( curCSSLeft ) || 0;
        }

        if ( jQuery.isFunction( options ) ) {
            options = options.call( elem, i, curOffset );
        }

        if ( options.top != null ) {
            props.top = ( options.top - curOffset.top ) + curTop;
        }
        if ( options.left != null ) {
            props.left = ( options.left - curOffset.left ) + curLeft;
        }

        if ( "using" in options ) {
            options.using.call( elem, props );

        } else {
            curElem.css( props );
        }
    }
};


jQuery.fn.extend({

    position: function() {
        if ( !this[ 0 ] ) {
            return;
        }

        var offsetParent, offset,
            elem = this[ 0 ],
            parentOffset = { top: 0, left: 0 };

        // Fixed elements are offset from window (parentOffset = {top:0, left: 0}, because it is it's only offset parent
        if ( jQuery.css( elem, "position" ) === "fixed" ) {
            // We assume that getBoundingClientRect is available when computed position is fixed
            offset = elem.getBoundingClientRect();

        } else {
            // Get *real* offsetParent
            offsetParent = this.offsetParent();

            // Get correct offsets
            offset = this.offset();
            if ( !jQuery.nodeName( offsetParent[ 0 ], "html" ) ) {
                parentOffset = offsetParent.offset();
            }

            // Add offsetParent borders
            parentOffset.top += jQuery.css( offsetParent[ 0 ], "borderTopWidth", true );
            parentOffset.left += jQuery.css( offsetParent[ 0 ], "borderLeftWidth", true );
        }

        // Subtract parent offsets and element margins
        return {
            top: offset.top - parentOffset.top - jQuery.css( elem, "marginTop", true ),
            left: offset.left - parentOffset.left - jQuery.css( elem, "marginLeft", true )
        };
    },

    offsetParent: function() {
        return this.map(function() {
            var offsetParent = this.offsetParent || docElem;

            while ( offsetParent && ( !jQuery.nodeName( offsetParent, "html" ) && jQuery.css( offsetParent, "position") === "static" ) ) {
                offsetParent = offsetParent.offsetParent;
            }

            return offsetParent || docElem;
        });
    }
});


// Create scrollLeft and scrollTop methods
jQuery.each( {scrollLeft: "pageXOffset", scrollTop: "pageYOffset"}, function( method, prop ) {
    var top = "pageYOffset" === prop;

    jQuery.fn[ method ] = function( val ) {
        return jQuery.access( this, function( elem, method, val ) {
            var win = getWindow( elem );

            if ( val === undefined ) {
                return win ? win[ prop ] : elem[ method ];
            }

            if ( win ) {
                win.scrollTo(
                    !top ? val : window.pageXOffset,
                    top ? val : window.pageYOffset
                );

            } else {
                elem[ method ] = val;
            }
        }, method, val, arguments.length, null );
    };
});

function getWindow( elem ) {
    return jQuery.isWindow( elem ) ? elem : elem.nodeType === 9 && elem.defaultView;
}
// Create innerHeight, innerWidth, height, width, outerHeight and outerWidth methods
jQuery.each( { Height: "height", Width: "width" }, function( name, type ) {
    jQuery.each( { padding: "inner" + name, content: type, "": "outer" + name }, function( defaultExtra, funcName ) {
        // margin is only for outerHeight, outerWidth
        jQuery.fn[ funcName ] = function( margin, value ) {
            var chainable = arguments.length && ( defaultExtra || typeof margin !== "boolean" ),
                extra = defaultExtra || ( margin === true || value === true ? "margin" : "border" );

            return jQuery.access( this, function( elem, type, value ) {
                var doc;

                if ( jQuery.isWindow( elem ) ) {
                    // As of 5/8/2012 this will yield incorrect results for Mobile Safari, but there
                    // isn't a whole lot we can do. See pull request at this URL for discussion:
                    // https://github.com/jquery/jquery/pull/764
                    return elem.document.documentElement[ "client" + name ];
                }

                // Get document width or height
                if ( elem.nodeType === 9 ) {
                    doc = elem.documentElement;

                    // Either scroll[Width/Height] or offset[Width/Height] or client[Width/Height],
                    // whichever is greatest
                    return Math.max(
                        elem.body[ "scroll" + name ], doc[ "scroll" + name ],
                        elem.body[ "offset" + name ], doc[ "offset" + name ],
                        doc[ "client" + name ]
                    );
                }

                return value === undefined ?
                    // Get width or height on the element, requesting but not forcing parseFloat
                    jQuery.css( elem, type, extra ) :

                    // Set width or height on the element
                    jQuery.style( elem, type, value, extra );
            }, type, chainable ? margin : undefined, chainable, null );
        };
    });
});
// Limit scope pollution from any deprecated API
// (function() {

// The number of elements contained in the matched element set
jQuery.fn.size = function() {
    return this.length;
};

jQuery.fn.andSelf = jQuery.fn.addBack;

// })();
if ( typeof module === "object" && module && typeof module.exports === "object" ) {
    // Expose jQuery as module.exports in loaders that implement the Node
    // module pattern (including browserify). Do not create the global, since
    // the user will be storing it themselves locally, and globals are frowned
    // upon in the Node module world.
    module.exports = jQuery;
} else {
    // Register as a named AMD module, since jQuery can be concatenated with other
    // files that may use define, but not via a proper concatenation script that
    // understands anonymous AMD modules. A named AMD is safest and most robust
    // way to register. Lowercase jquery is used because AMD module names are
    // derived from file names, and jQuery is normally delivered in a lowercase
    // file name. Do this after creating the global so that if an AMD module wants
    // to call noConflict to hide this version of jQuery, it will work.
    if ( typeof define === "function" && define.amd ) {
        define( "jquery", [], function () { return jQuery; } );
    }
}

// If there is a window object, that at least has a document property,
// define jQuery and $ identifiers
if ( typeof window === "object" && typeof window.document === "object" ) {
    //对外提供了接口,这样匿名函数中的jQuery就可以找到了,因为挂载到了window下
    window.jQuery = window.$ = jQuery;
}

})( window );
很惭愧<br><br>只做了一点微小的工作<br>谢谢大家