jQuery在1.5引入了Deferred对象（异步列队），当时它还没有划分为一个模块，放到核心模块中。直到1.52才分割出来。它拥有三个方法:_Deferred， Deferred与when。
出于变量在不同作用域的共用，jQuery实现异步列队时不使用面向对象方式，它把_Deferred当作一个工厂方法，返回一个不透明的函数列队。之所以说不透明，是因为它的状态与元素都以闭包手段保护起来，只能通过列队对象提供的方法进行操作。这几个方法分别是done(添加函数)，resolveWith（指定作用域地执行所有函数），resolve（执行所有函数），isResolved（判定是否已经调用过resolveWith或resolve方法），cancel（中断执行操作）。但_Deferred自始至终都作为一个内部方法，从没有在文档中公开过。
Deferred在1.5是两个_Deferred的合体，但1+1不等于2，它还是做了增强。偷偷爆料，Deferred本来是python世界大名鼎鼎的Twisted框架的东西，由早期七大JS类库中的MochiKit取经回来，最后被dojo继承衣钵。jQuery之所以这样构造Deferred，分明不愿背抄袭的恶名，于是方法改得一塌糊涂，是jQuery命名最差的API，完全不知所云。它还加入当时正在热烈讨论的promise机制。下面是一个比较列表：dojojQuery注解addBoththen同时添加正常回调与错误回调addCallbackdone添加正常回调addErrbackfail添加错误回调callbackdone执行所有正常回调errbackreject执行所有错误回调doneWith在指定作用域下执行所有正常回调，但dojo已经在addCallback上指定好了rejectWith在指定作用域下执行所有错误回调，但dojo已经在addErrback上指定好了promise返回一个外界不能改变其状态的Deferred对象（外称为Promise对象）
jQuery的when方法用于实现回调的回调，或者说，几个异列列队都执行后才执行另外的一些回调。这些后来的回调也是用done, when, fail添加的，但when返回的这个对象已经添加让用户控制它执行的能力了。因为这时它是种叫Promise的东西，只负责添加回调与让用户窥探其状态。一旦前一段回调都触发了，它就自然进入正常回调列队（deferred ，见Deferred方法的定义）或错误回调列队（failDeferred ）中去。不过我这样讲，对于没有异步编程经验的人来说，肯定听得云里雾里。看实例好了。
复制代码代码如下:$.when({aa:1}, {aa:2}).done(function(a,b){console.log(a.aa) console.log(b.aa)});直接输出1,2。如果是传入两个函数，也是返回两个函数。因此对于普通的数据类型，前面的when有多少个参数，后面的done, fail方法的回调就有多少个参数。
复制代码代码如下:function fn(){return 4;}function log(s){window.console && console.log(s)}$.when( { num:1 }, 2, '3', fn() ).done(function(o1, o2, o3, o4){log(o1.num);log(o2);log(o3);log(o4);});如果我们想得到各个异步的结果，我们需要用resolve, resolveWith, reject, rejectWith进行传递它们。
复制代码代码如下:var log = function(msg){window.console && console.log(msg)}function asyncThing1(){var dfd = $.Deferred();setTimeout(function(){log('asyncThing1 seems to be done...');dfd.resolve('1111');},1000);return dfd.promise();}function asyncThing2(){var dfd = $.Deferred();setTimeout(function(){log('asyncThing2 seems to be done...');dfd.resolve('222');},1500);return dfd.promise();}function asyncThing3(){var dfd = $.Deferred();setTimeout(function(){log('asyncThing3 seems to be done...');dfd.resolve('333');},2000);return dfd.promise();}/* do it */$.when( asyncThing1(), asyncThing2(), asyncThing3() ).done(function(res1, res2, res3){log('all done!');log(res1 + ', ' + res2 + ', ' + res3);})异步列队一开始没什么人用（现在也没有什么人用，概念太抽象了，方法名起得太烂了），于是它只能在内部自产自销。首先被染指的是queue。queue模块是1.4为吸引社区的delay插件，特地从data模块中分化的产物，而data则是从event模块化分出来的。jQuery新模块的诞生总是因为用户对已有API的局限制不满而致。最早的queue模块的源码：复制代码代码如下:jQuery.extend({queue: function( elem, type, data ) {if ( !elem ) {return;}type = (type || "fx") + "queue";var q = jQuery.data( elem, type );// Speed up dequeue by getting out quickly if this is just a lookup if ( !data ) {return q || [];}if ( !q || jQuery.isArray(data) ) {q = jQuery.data( elem, type, jQuery.makeArray(data) );} else {q.push( data );}return q;},dequeue: function( elem, type ) {type = type || "fx";var queue = jQuery.queue( elem, type ), fn = queue.shift();// If the fx queue is dequeued, always remove the progress sentinel if ( fn === "inprogress" ) {fn = queue.shift();}if ( fn ) {// Add a progress sentinel to prevent the fx queue from being// automatically dequeued if ( type === "fx" ) {queue.unshift("inprogress");}fn.call(elem, function() {jQuery.dequeue(elem, type);});}}});jQuery.fn.extend({queue: function( type, data ) {if ( typeof type !== "string" ) {data = type;type = "fx";}if ( data === undefined ) {return jQuery.queue( this[0], type );}return this.each(function( i, elem ) {var queue = jQuery.queue( this, type, data );if ( type === "fx" && queue[0] !== "inprogress" ) {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() {var elem = this;setTimeout(function() {jQuery.dequeue( elem, type );}, time );});},clearQueue: function( type ) {return this.queue( type || "fx", [] );}});1.6添加了_mark,_unmark，promise。queue是让函数同属一个队伍里面，目的是让动画一个接一个执行。_mark则是让它们各自拥有队伍，并列执行（虽然它们只记录异步列队中已被执行的函数个数）。promise则在这些并发执行的动画执行后才执行另些一些回调（或动画）。
复制代码代码如下:(function( jQuery ) {function handleQueueMarkDefer( elem, type, src ) {//清空记录deferred个数的字段，函数列队与异步列队var deferDataKey = type + "defer",queueDataKey = type + "queue",markDataKey = type + "mark",defer = jQuery.data( elem, deferDataKey, undefined, true );if ( defer &&( src === "queue" || !jQuery.data( elem, queueDataKey, undefined, true ) ) &&( src === "mark" || !jQuery.data( elem, markDataKey, undefined, true ) ) ) {// Give room for hard-coded callbacks to fire first// and eventually mark/queue something else on the element setTimeout( function() {if ( !jQuery.data( elem, queueDataKey, undefined, true ) &&!jQuery.data( elem, markDataKey, undefined, true ) ) {jQuery.removeData( elem, deferDataKey, true );defer.resolve();}}, 0 );}}jQuery.extend({_mark: function( elem, type ) {if ( elem ) {type = (type || "fx") + "mark";//创建一个以mark为后缀的字段，用于记录此列队中个数jQuery.data( elem, type, (jQuery.data(elem,type,undefined,true) || 0) + 1, true );}},_unmark: function( force, elem, type ) {if ( force !== true ) {type = elem;elem = force;force = false;}if ( elem ) {type = type || "fx";var key = type + "mark",//让个数减1，如果第一个参数为true，就强逼减至0 count = force ? 0 : ( (jQuery.data( elem, key, undefined, true) || 1 ) - 1 );if ( count ) {jQuery.data( elem, key, count, true );} else {//如果为0，就移除它jQuery.removeData( elem, key, true );handleQueueMarkDefer( elem, type, "mark" );}}},queue: function( elem, type, data ) {if ( elem ) {type = (type || "fx") + "queue";var q = jQuery.data( elem, type, undefined, true );// Speed up dequeue by getting out quickly if this is just a lookup if ( data ) {if ( !q || jQuery.isArray(data) ) {q = jQuery.data( elem, type, jQuery.makeArray(data), true );} else {q.push( data );}}return q || [];}},dequeue: function( elem, type ) {type = type || "fx";var queue = jQuery.queue( elem, type ),fn = queue.shift(),defer;// If the fx queue is dequeued, always remove the progress sentinel if ( fn === "inprogress" ) {fn = queue.shift();}if ( fn ) {// Add a progress sentinel to prevent the fx queue from being// automatically dequeued if ( type === "fx" ) {queue.unshift("inprogress");}fn.call(elem, function() {jQuery.dequeue(elem, type);});}if ( !queue.length ) {jQuery.removeData( elem, type + "queue", true );handleQueueMarkDefer( elem, type, "queue" );}}});jQuery.fn.extend({queue: function( type, data ) {if ( typeof type !== "string" ) {data = type;type = "fx";}if ( data === undefined ) {return jQuery.queue( this[0], type );}return this.each(function() {var queue = jQuery.queue( this, type, data );if ( type === "fx" && queue[0] !== "inprogress" ) {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() {var elem = this;setTimeout(function() {jQuery.dequeue( elem, type );}, time );});},clearQueue: function( type ) {return this.queue( type || "fx", [] );},//把jQuery对象装进一个异步列队，允许它在一系列动画中再执行之后绑定的回调promise: function( type, object ) {if ( typeof type !== "string" ) {object = type;type = undefined;}type = type || "fx";var defer = jQuery.Deferred(),elements = this,i = elements.length,count = 1,deferDataKey = type + "defer",queueDataKey = type + "queue",markDataKey = type + "mark";function resolve() {if ( !( --count ) ) {defer.resolveWith( elements, [ elements ] );}}while( i-- ) {//如果它之前已经使用过unmark, queue等方法，那么我们将生成一个新的Deferred放进缓存系统if (( tmp = jQuery.data( elements[ i ], deferDataKey, undefined, true ) ||( jQuery.data( elements[ i ], queueDataKey, undefined, true ) ||jQuery.data( elements[ i ], markDataKey, undefined, true ) ) &&jQuery.data( elements[ i ], deferDataKey, jQuery._Deferred(), true ) )) {count++;tmp.done( resolve );}}resolve();return defer.promise();}});})( jQuery );jQuery.ajax模块也被染指，$.XHR对象，当作HTTPXMLRequest对象的仿造器是由一个Deferred对象与一个_Deferred的对象构成。
复制代码代码如下:deferred = jQuery.Deferred(),completeDeferred = jQuery._Deferred(),jqXHR ={/**/}//....
deferred.promise( jqXHR );jqXHR.success = jqXHR.done;jqXHR.error = jqXHR.fail;jqXHR.complete = completeDeferred.done;jQuery1.7，从deferred模块中分化出callback模块，其实就是之前的_Deferred的增强版，添加去重，锁定，return false时中断执行下一个回调，清空等功能。
复制代码代码如下:(function( jQuery ) {// String to Object flags format cache var flagsCache = {};// Convert String-formatted flags into Object-formatted ones and store in cache function createFlags( flags ) {var object = flagsCache[ flags ] = {},i, length;flags = flags.split( /\s+/ );for ( i = 0, length = flags.length; i object[ flags[i] ] = true;}return object;}/** Create a callback list using the following parameters:** flags: an optional list of space-separated flags that will change how* the callback list behaves** By default a callback list will act like an event callback list and can be* "fired" multiple times.
** Possible flags:** 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)** unique: will ensure a callback can only be added once (no duplicate in the list)** stopOnFalse: interrupt callings when a callback returns false**/ jQuery.Callbacks = function( flags ) {// Convert flags from String-formatted to Object-formatted// (we check in cache first) flags = flags ? ( flagsCache[ flags ] || createFlags( flags ) ) : {};var // Actual callback list list = [],// Stack of fire calls for repeatable lists stack = [],// Last fire value (for non-forgettable lists) memory,// Flag to know if list is currently firing firing,// First callback to fire (used internally by add and fireWith) firingStart,// End of the loop when firing firingLength,// Index of currently firing callback (modified by remove if needed) firingIndex,// Add one or several callbacks to the list add = function( args ) {var i,length,elem,type,actual;for ( i = 0, length = args.length; i elem = args[ i ];type = jQuery.type( elem );if ( type === "array" ) {// Inspect recursively add( elem );} else if ( type === "function" ) {// Add if not in unique mode and callback is not in if ( !flags.unique || !self.has( elem ) ) {list.push( elem );}}}},// Fire callbacks fire = function( context, args ) {args = args || [];memory = !flags.memory || [ context, args ];firing = true;firingIndex = firingStart || 0;firingStart = 0;firingLength = list.length;for ( ; list && firingIndex if ( list[ firingIndex ].apply( context, args ) === false && flags.stopOnFalse ) {memory = true; // Mark as halted break;}}firing = false;if ( list ) {if ( !flags.once ) {if ( stack && stack.length ) {memory = stack.shift();self.fireWith( memory[ 0 ], memory[ 1 ] );}} else if ( memory === true ) {self.disable();} else {list = [];}}},// Actual Callbacks object self = {// Add a callback or a collection of callbacks to the list add: function() {if ( list ) {var length = list.length;add( arguments );// Do we need to add the callbacks to the// current firing batch?if ( firing ) {firingLength = list.length;// With memory, if we're not firing then// we should call right away, unless previous// firing was halted (stopOnFalse)} else if ( memory && memory !== true ) {firingStart = length;fire( memory[ 0 ], memory[ 1 ] );}}return this;},// Remove a callback from the list remove: function() {if ( list ) {var args = arguments,argIndex = 0,argLength = args.length;for ( ; argIndex for ( var i = 0; i if ( args[ argIndex ] === list[ i ] ) {// Handle firingIndex and firingLength if ( firing ) {if ( i firingLength--;if ( i firingIndex--;}}}// Remove the element list.splice( i--, 1 );// If we have some unicity property then// we only need to do this once if ( flags.unique ) {break;}}}}}return this;},// Control if a given callback is in the list has: function( fn ) {if ( list ) {var i = 0,length = list.length;for ( ; i if ( fn === list[ i ] ) {return true;}}}return false;},// Remove all callbacks from the list empty: function() {list = [];return this;},// Have the list do nothing anymore disable: function() {list = stack = memory = undefined;return this;},// Is it disabled?disabled: function() {return !list;},// Lock the list in its current state lock: function() {stack = undefined;if ( !memory || memory === true ) {self.disable();}return this;},// Is it locked?locked: function() {return !stack;},// Call all callbacks with the given context and arguments fireWith: function( context, args ) {if ( stack ) {if ( firing ) {if ( !flags.once ) {stack.push( [ context, args ] );}} else if ( !( flags.once && memory ) ) {fire( context, args );}}return this;},// Call all the callbacks with the given arguments fire: function() {self.fireWith( this, arguments );return this;},// To know if the callbacks have already been called at least once fired: function() {return !!memory;}};return self;};})( jQuery );这期间有还个小插曲，jQuery团队还想增加一个叫Topic的模块，内置发布者订阅者机制，但这封装太溥了，结果被否决。
复制代码代码如下:(function( jQuery ) {var topics = {},sliceTopic = [].slice;jQuery.Topic = function( id ) {var callbacks,method,topic = id && topics[ id ];if ( !topic ) {callbacks = jQuery.Callbacks();topic = {publish: callbacks.fire,subscribe: callbacks.add,unsubscribe: callbacks.remove};if ( id ) {topics[ id ] = topic;}}return topic;};jQuery.extend({subscribe: function( id ) {var topic = jQuery.Topic( id ),args = sliceTopic.call( arguments, 1 );topic.subscribe.apply( topic, args );return {topic: topic,args: args};},unsubscribe: function( id ) {var topic = id && id.topic || jQuery.Topic( id );topic.unsubscribe.apply( topic, id && id.args ||sliceTopic.call( arguments, 1 ) );},publish: function( id ) {var topic = jQuery.Topic( id );topic.publish.apply( topic, sliceTopic.call( arguments, 1 ) );}});})( jQuery );虽然把大量代码移动callbacks，但1.7的Deferred却一点没有没变小，它变得更重型，它由三个函数列队组成了。并且返回的是Promise对象，比原来多出了pipe, state, progress, always方法。ajax那边就变成这样：复制代码代码如下:deferred = jQuery.Deferred(),completeDeferred = jQuery.Callbacks( "once memory" ),deferred.promise( jqXHR );jqXHR.success = jqXHR.done;jqXHR.error = jqXHR.fail;jqXHR.complete = completeDeferred.add;queue那边也没变多少。
复制代码代码如下:(function( jQuery ) {function handleQueueMarkDefer( elem, type, src ) {var deferDataKey = type + "defer",queueDataKey = type + "queue",markDataKey = type + "mark",defer = jQuery._data( elem, deferDataKey );if ( defer &&( src === "queue" || !jQuery._data(elem, queueDataKey) ) &&( src === "mark" || !jQuery._data(elem, markDataKey) ) ) {// Give room for hard-coded callbacks to fire first// and eventually mark/queue something else on the element setTimeout( function() {if ( !jQuery._data( elem, queueDataKey ) &&!jQuery._data( elem, markDataKey ) ) {jQuery.removeData( elem, deferDataKey, true );defer.fire();}}, 0 );}}jQuery.extend({_mark: function( elem, type ) {if ( elem ) {type = ( type || "fx" ) + "mark";jQuery._data( elem, type, (jQuery._data( elem, type ) || 0) + 1 );}},_unmark: function( force, elem, type ) {if ( force !== true ) {type = elem;elem = force;force = false;}if ( elem ) {type = type || "fx";var key = type + "mark",count = force ? 0 : ( (jQuery._data( elem, key ) || 1) - 1 );if ( count ) {jQuery._data( elem, key, count );} else {jQuery.removeData( elem, key, true );handleQueueMarkDefer( elem, type, "mark" );}}},queue: function( elem, type, data ) {var q;if ( elem ) {type = ( type || "fx" ) + "queue";q = jQuery._data( elem, type );// Speed up dequeue by getting out quickly if this is just a lookup if ( data ) {if ( !q || jQuery.isArray(data) ) {q = jQuery._data( elem, type, jQuery.makeArray(data) );} else {q.push( data );}}return q || [];}},dequeue: function( elem, type ) {type = type || "fx";var queue = jQuery.queue( elem, type ),fn = queue.shift(),hooks = {};// If the fx queue is dequeued, always remove the progress sentinel if ( fn === "inprogress" ) {fn = queue.shift();}if ( fn ) {// Add a progress sentinel to prevent the fx queue from being// automatically dequeued if ( type === "fx" ) {queue.unshift( "inprogress" );}jQuery._data( elem, type + ".run", hooks );fn.call( elem, function() {jQuery.dequeue( elem, type );}, hooks );}if ( !queue.length ) {jQuery.removeData( elem, type + "queue " + type + ".run", true );handleQueueMarkDefer( elem, type, "queue" );}}});jQuery.fn.extend({queue: function( type, data ) {var setter = 2;if ( typeof type !== "string" ) {data = type;type = "fx";setter--;}if ( arguments.length return jQuery.queue( this[0], type );}return data === undefined ?this :this.each(function() {var queue = jQuery.queue( this, type, data );if ( type === "fx" && queue[0] !== "inprogress" ) {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, object ) {if ( typeof type !== "string" ) {object = type;type = undefined;}type = type || "fx";var defer = jQuery.Deferred(),elements = this,i = elements.length,count = 1,deferDataKey = type + "defer",queueDataKey = type + "queue",markDataKey = type + "mark",tmp;function resolve() {if ( !( --count ) ) {defer.resolveWith( elements, [ elements ] );}}while( i-- ) {if (( tmp = jQuery.data( elements[ i ], deferDataKey, undefined, true ) ||( jQuery.data( elements[ i ], queueDataKey, undefined, true ) ||jQuery.data( elements[ i ], markDataKey, undefined, true ) ) &&jQuery.data( elements[ i ], deferDataKey, jQuery.Callbacks( "once memory" ), true ) )) {count++;tmp.add( resolve );}}resolve();return defer.promise( object );}});})( jQuery );这时候，钩子机制其实已经在jQuery内部蔓延起来，1.5是css模块的cssHooks，1.6是属性模块的attrHooks, propHooks, boolHooks, nodeHooks,1.7是事件模块的fixHooks， keyHooks, mouseHooks,1.8是queue模块的_queueHooks，由于_queueHooks，queue终于瘦身了。
复制代码代码如下:View Code?//1.8 jQuery.extend({queue: function( elem, type, data ) {var queue;if ( elem ) {type = ( type || "fx" ) + "queue";queue = jQuery._data( elem, type );// Speed up dequeue by getting out quickly if this is just a lookup if ( data ) {if ( !queue || jQuery.isArray(data) ) {queue = jQuery._data( elem, type, jQuery.makeArray(data) );} else {queue.push( data );}}return queue || [];}},dequeue: function( elem, type ) {type = type || "fx";var queue = jQuery.queue( elem, type ),fn = queue.shift(),hooks = jQuery._queueHooks( elem, type ),next = function() {jQuery.dequeue( elem, type );};// If the fx queue is dequeued, always remove the progress sentinel if ( fn === "inprogress" ) {fn = queue.shift();}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;fn.call( elem, next, hooks );}if ( !queue.length && hooks ) {hooks.empty.fire();}},// not intended for public consumption - generates a queueHooks object, or returns the current one_queueHooks: function( elem, type ) {var key = type + "queueHooks";return jQuery._data( elem, key ) || jQuery._data( elem, key, {empty: jQuery.Callbacks("once memory").add(function() {jQuery.removeData( elem, type + "queue", true );jQuery.removeData( elem, key, true );})});}});jQuery.fn.extend({queue: function( type, data ) {var setter = 2;if ( typeof type !== "string" ) {data = type;type = "fx";setter--;}if ( arguments.length return jQuery.queue( this[0], type );}return data === undefined ?this :this.each(function() {var queue = jQuery.queue( this, type, data );// ensure a hooks for this queue jQuery._queueHooks( this, type );if ( type === "fx" && queue[0] !== "inprogress" ) {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-- ) {if ( (tmp = jQuery._data( elements[ i ], type + "queueHooks" )) && tmp.empty ) {count++;tmp.empty.add( resolve );}}resolve();return defer.promise( obj );}});同时，动画模块迎来了它第三次大重构，它也有一个钩子Tween.propHooks。它多出两个对象，其中Animation返回一个异步列队，Tween 是用于处理单个样式或属性的变化，相当于之前Fx对象。animate被抽空了，它在1.72可是近百行的规模。jQuery通过钩子机制与分化出一些新的对象，将一些巨型方法重构掉。现在非常长的方法只龟缩在节点模块，回调模块。
复制代码代码如下: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 resolve immediately if ( empty ) {anim.stop( true );}};return empty || optall.queue === false ?this.each( doAnimation ) :this.queue( optall.queue, doAnimation );},到目前为止，所有异步的东西都被jQuery改造成异步列队的“子类”或叫“变种”更合适些。如domReady, 动画，AJAX，与执行了promise或delay或各种特效方法之后的jQuery对象。于是所有异步的东西在promise的加护下，像同步那样编写异步程序。