【Prototype 1.4.0】源码解读----全文注释版

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/*  Prototype JavaScript framework, version 1.4.0 *  (c) 2005 Sam Stephenson <sam@conio.net> * *  Prototype is freely distributable under the terms of an MIT-style license. *  For details, see the Prototype web site: http://prototype.conio.net/  *  这是一个JavaScript的框架,致力于简化动态的Web开发,完全按照面对对象的思想 *  进行Javascript开发,添加了迭代器的概念增强Javascript的设计能力。 *  Prototype框架构思独特充满了技巧性的代码,方便易用的工具类! */*--------------------------------------------------------------------------*/   /* 【Prototype】定义一个全局对象,提供一个全局的基本信息和工具 */var Prototype = {  Version: '1.4.0', //可以作为版本检测用//用于脚本检测的正则表达式,经常使用所以放在这里起到全局常量的作用  ScriptFragment: '(?:<script.*?>)((\n|\r|.)*?)(?:<\/script>)',  emptyFunction: function() {},//空函数  K: function(x) {return x}//K方法返回参数本身,在后面经常用到}/*========================================================================================*//* *【Class】对象的作用只有一个就是提供了一个定义类的模式 * 仅含有create 一个方法,返回一个构造函数。  * 一般使用如下   *     var X = Class.create();  返回一个类型   * 要使用 X 类型,需继续用 new X()来获取一个实例 这与C# JAVA类似 * 返回的构造函数会执行名为 initialize 的方法, initialize 是 Ruby 对象的构造器方法名字。  * 此时initialize方法还没有定义,其后的代码中创建新类型时会建立相应的同名方法,可以看作是一个抽象方法。  * 从C#角度讲可以理解为用Class.create()创建一个继承Object基类的类。  *  */ var Class = {  create: function() {    return function() {  //下面使用Apply方法传递参数是一个常用的技巧      this.initialize.apply(this, arguments);    }  }}/*========================================================================================*///Abstract是一个空对象,它的作用仅仅是作为一个抽象的命名空间,所有在该对象下定义的类都是抽象类//从而从形式上与实体类分开var Abstract = new Object();/* *Object是所有对象的基类,这个基类有两个静态方法 */ //把Source的所有属性和方法传递给Destination,实现了继承的效果Object.extend = function(destination, source) {  for (property in source) {    destination[property] = source[property];  }  return destination;}//观察Object的组成,需要参数中的object实现自己的inspect方法Object.inspect = function(object) {  try {    if (object == undefined) return 'undefined';    if (object == null) return 'null';    return object.inspect ? object.inspect() : object.toString();  } catch (e) {    if (e instanceof RangeError) return '';    throw e;  }}/*========================================================================================*///【Function】是所有函数对象的基类,可以通过对它的扩展实现对所有函数对象添加功能/* 这里在绑定的时候旧可以传递参数而不是调用的时候才指定参数,bind方法接收多个参数  将函数绑定到第一个参数指定的对象上,并返回该方法的调用句柄*/Function.prototype.bind = function() {  // $A()方法的作用是把参数专为数组   //数组的shift方法作用是删除数组的第一个元素  var __method = this, args = $A(arguments), object = args.shift();  return function() {    return __method.apply(object, args.concat($A(arguments)));    //这里的$A(arguments)是条用返回函数句柄时传递的参数,不是bind方法的参数  }}/**  * 和bind一样,不过这个方法一般用做html控件对象的事件处理。所以要传递event对象  * 好像是重载了_method方法 */ Function.prototype.bindAsEventListener = function(object) {  var __method = this;  return function(event) {    return __method.call(object, event || window.event);  }}/*========================================================================================*///【Function】是所有数值类型的基类Object.extend(Number.prototype, {  toColorPart: function() {           //RGB-》16进制颜色    var digits = this.toString(16);    if (this < 16) return '0' + digits;    return digits;  },  succ: function() { //数值加一 var a=1; var b=a.succ; 那么b=2    return this + 1;  },  times: function(iterator) {   //这里的参数iterator是一个迭代器作用就是循环调用指定次数的iterator函数  //$R(start,end,exclusive)是创建ObjectRnge对象的快捷方式    $R(0, this, true).each(iterator);    return this;  }});/*========================================================================================*///提供了一个方法these,要求参数是函数的句柄,可以有多个。作用就是返回第一个成功执行的函数的返回值var Try = {  these: function() {    var returnValue;    for (var i = 0; i < arguments.length; i++) {      var lambda = arguments[i];      try {        returnValue = lambda();        break;      } catch (e) {}    }    return returnValue;  }}/*========================================================================================*///定时器类用来实现Window.setInterval的效果,在给定时间间隔执行某一个函数,增加了对重复执行的控制Svar PeriodicalExecuter = Class.create();PeriodicalExecuter.prototype = {  initialize: function(callback, frequency) {  //构造函数指定回调函数和执行频率,单位是秒    this.callback = callback;    this.frequency = frequency;    this.currentlyExecuting = false;    this.registerCallback();  },  /* 开始调用定时器,无需显示调用,在构造函数中就实现了自动调用,这一下面的this.onTimerEvent.bind(this)如果写成this.onTimerEvent则this指针就会指向widows对象即setInterval的默认对象从而不能正确的引用到下面两个函数上,也就失去了对正在执行函数的控制*/  registerCallback: function() {    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);  },//下面的函数相当于是回调函数的一个代理, setInterval是到了指定的时间就会强制执行而这里//加入了一个判断如果callback函数执行的时间超过了一个时间片,则阻止其被重复执行  onTimerEvent: function() {    if (!this.currentlyExecuting) {      try {        this.currentlyExecuting = true;        this.callback();      } finally {        this.currentlyExecuting = false;      }    }  }}/*使用举例:function GetOnlineCount(){//获得在线人数}new PeriodicalExecuter(GetOnlineCount,10)每10秒获取一次*//*========================================================================================*//* 框架核心内容--------【基础工具类】/*========================================================================================*/ /*document.getElementById(id)获取一个指定ID的结点,是这个方法的快捷方式和扩展 可以指定多个参数返回一个对象数组。参数也不一定是ID也可以是对象本身的引用,例如 $('id')等价于$($('id'))  */function $() {  var elements = new Array();  for (var i = 0; i < arguments.length; i++) {    var element = arguments[i];    if (typeof element == 'string')      element = document.getElementById(element);    if (arguments.length == 1)      return element;    elements.push(element);  }  return elements;}/*========================================================================================*///【String】类的扩展//删除字符串中的HTML标记Object.extend(String.prototype, {  stripTags: function() {    return this.replace(/<\/?[^>]+>/gi, '');  },//删除字符串中的脚本块  stripScripts: function() {    return this.replace(new RegExp(Prototype.ScriptFragment, 'img'), '');  },//提取字符串中的所有脚本块,作为数组返回,每一个脚本作为一个数组元素  extractScripts: function() {    var matchAll = new RegExp(Prototype.ScriptFragment, 'img');    var matchOne = new RegExp(Prototype.ScriptFragment, 'im');    return (this.match(matchAll) || []).map(function(scriptTag) {      return (scriptTag.match(matchOne) || ['', ''])[1];    });  },//提取字符串中的脚本并执行  evalScripts: function() {    return this.extractScripts().map(eval);  },//将字符串进行html编码例如"<" --》"<"  escapeHTML: function() {    var div = document.createElement('div');    var text = document.createTextNode(this);    div.appendChild(text);    return div.innerHTML;  },//对字符串进行html解码例如"<"--》"<"  unescapeHTML: function() {    var div = document.createElement('div');    div.innerHTML = this.stripTags();    return div.childNodes[0] ? div.childNodes[0].nodeValue : '';  },//将查询字符串格式的字符串转换为键值对数组//例如var s="a=1&b=2&c=3"; var s2=s.toQueryParams(); s2为{a:1,b:2,c:3}  toQueryParams: function() {    var pairs = this.match(/^\??(.*)$/)[1].split('&');    return pairs.inject({}, function(params, pairString) {      var pair = pairString.split('=');      params[pair[0]] = pair[1];      return params;    });  },//字符串转换为字符数组 "abc"-->['a','b','c']  toArray: function() {    return this.split('');  },//连字符--》骆驼样式 'good-man'-->'goodMan'  camelize: function() {    var oStringList = this.split('-');    if (oStringList.length == 1) return oStringList[0];    var camelizedString = this.indexOf('-') == 0      ? oStringList[0].charAt(0).toUpperCase() + oStringList[0].substring(1)      : oStringList[0];    for (var i = 1, len = oStringList.length; i < len; i++) {      var s = oStringList[i];      camelizedString += s.charAt(0).toUpperCase() + s.substring(1);    }    return camelizedString;  },//得到字符串的组成结构  inspect: function() {    return "'" + this.replace('\\', '\\\\').replace("'", '\\\'') + "'";  }});//定义了一个等价的函数String.prototype.parseQuery = String.prototype.toQueryParams;/*========================================================================================*///【Enumerable】可枚举接口 是整个1.4.0框架的核心工具,所有实现此接口的类必须要实现_each(iterator)方法var $break    = new Object(); //首先定义了两个异常对象,用于进行迭代计算的控制var $continue = new Object();var Enumerable = {//用于对对象的每一个元素遍历执行iterator迭代器函数  each: function(iterator) {    var index = 0;                //可选参数表示元素在枚举对象的次序    try {      this._each(function(value) {//value是枚举元素的值        try {          iterator(value, index++);        } catch (e) {          if (e != $continue) throw e;        }      });    } catch (e) {      if (e != $break) throw e;    }  },//判断是否所有的枚举元素都能使iterator返回true  all: function(iterator) {    var result = true;    this.each(function(value, index) {      result = result && !!(iterator || Prototype.K)(value, index);      if (!result) throw $break;    });    return result;  },//判断是否有枚举元素能使iterator返回true,有一个就是True  any: function(iterator) {    var result = true;    this.each(function(value, index) {      if (result = !!(iterator || Prototype.K)(value, index))        throw $break;    });    return result;  },//对所有的枚举元素执行iterator迭代器函数 结果作为一个数组返回  collect: function(iterator) {    var results = [];    this.each(function(value, index) {      results.push(iterator(value, index));    });    return results;  },//第一个素能使iterator返回true的枚举元素的值,没有返回undefined  detect: function (iterator) {    var result;    this.each(function(value, index) {      if (iterator(value, index)) {        result = value;        throw $break;      }    });    return result;  },//找到所有的能使iterator迭代器函数返回true的枚举元素 作为一个数组返回  findAll: function(iterator) {    var results = [];    this.each(function(value, index) {      if (iterator(value, index))        results.push(value);    });    return results;  },//找到素有匹配pattern的枚举元素,结果作为数组返回,iterator可选,如果不指定旧返回素有匹配pattern的枚举元素  grep: function(pattern, iterator) {//正则模式 迭代器    var results = [];    this.each(function(value, index) {      var stringValue = value.toString();      if (stringValue.match(pattern))        results.push((iterator || Prototype.K)(value, index));    })    return results;  },//判断枚举对象中是否含有参数Object指定的值  include: function(object) {    var found = false;    this.each(function(value) {      if (value == object) {        found = true;        throw $break;      }    });    return found;  },//将memo作为iterator的第一个参数,枚举元素作为iterator的第二个参数,枚举元素的次序作为第三个//参数每次迭代器的返回值将作为下一个iterator的memo参数,从而所有的迭代执行都通过memo联系起来了  inject: function(memo, iterator) {    this.each(function(value, index) {      memo = iterator(memo, value, index);    });    return memo;  },//对所有的枚举元素执行method方法 后面是要传递的参数  invoke: function(method) {    var args = $A(arguments).slice(1);    return this.collect(function(value) {      return value[method].apply(value, args);    });  },//返回的最大的迭代器执行结果  max: function(iterator) {    var result;    this.each(function(value, index) {      value = (iterator || Prototype.K)(value, index);      if (value >= (result || value))        result = value;    });    return result;  },//反之  min: function(iterator) {    var result;    this.each(function(value, index) {      value = (iterator || Prototype.K)(value, index);      if (value <= (result || value))        result = value;    });    return result;  },//返回两个数组一组能使iterator返回true 另一组返回false  partition: function(iterator) {    var trues = [], falses = [];    this.each(function(value, index) {      ((iterator || Prototype.K)(value, index) ?        trues : falses).push(value);    });    return [trues, falses];  },//获取所有枚举元素的property属性值作为数组的返回  pluck: function(property) {    var results = [];    this.each(function(value, index) {      results.push(value[property]);    });    return results;  },//与findall相反   reject: function(iterator) {    var results = [];    this.each(function(value, index) {      if (!iterator(value, index))        results.push(value);    });    return results;  },//根据iterator的结果排序 最小的在前面 作为数组返回  sortBy: function(iterator) {    return this.collect(function(value, index) {      return {value: value, criteria: iterator(value, index)};    }).sort(function(left, right) {      var a = left.criteria, b = right.criteria;      return a < b ? -1 : a > b ? 1 : 0;    }).pluck('value');  },//枚举对象--》数组  toArray: function() {    return this.collect(Prototype.K);  },//接收多个枚举对象参数,最后一个可以是迭代器用于阵列转换  zip: function() {    var iterator = Prototype.K, args = $A(arguments);    if (typeof args.last() == 'function')      iterator = args.pop();    var collections = [this].concat(args).map($A);    return this.map(function(value, index) {      iterator(value = collections.pluck(index));      return value;    });  },//返回枚举对象的字符串描述  inspect: function() {    return '#<Enumerable:' + this.toArray().inspect() + '>';  }}//等价函数定义Object.extend(Enumerable, {  map:     Enumerable.collect,  find:    Enumerable.detect,  select:  Enumerable.findAll,  member:  Enumerable.include,  entries: Enumerable.toArray});/*========================================================================================*///【Array】数组对象//参数转换为数组,如果参数定义了toarray则直接调用,否则枚举获得数组var $A = Array.from = function(iterable) {  if (!iterable) return [];  if (iterable.toArray) {    return iterable.toArray();  } else {    var results = [];    for (var i = 0; i < iterable.length; i++)      results.push(iterable[i]);    return results;  }}//数组对象继承了Enumerable接口Object.extend(Array.prototype, Enumerable);Array.prototype._reverse = Array.prototype.reverse;Object.extend(Array.prototype, {//实现了枚举接口方法,用于对数组内的元素执行迭代器  _each: function(iterator) {    for (var i = 0; i < this.length; i++)      iterator(this[i]);  },//清空数组  clear: function() {    this.length = 0;    return this;  },//取得第一个元素  first: function() {    return this[0];  },//取得最后一个元素  last: function() {    return this[this.length - 1];  },//删除数组元素中所有的null undefined值 作为新数组返回,原数组不受影响  compact: function() {    return this.select(function(value) {      return value != undefined || value != null;    });  },//展开所有数组元素不再嵌套  flatten: function() {    return this.inject([], function(array, value) {      return array.concat(value.constructor == Array ?        value.flatten() : [value]);    });  },//数组中删除指定的元素,返回删除后的结果,原数组不受影响  without: function() {    var values = $A(arguments);    return this.select(function(value) {      return !values.include(value);    });  },//Value元素在数组中的索引值  indexOf: function(object) {    for (var i = 0; i < this.length; i++)      if (this[i] == object) return i;    return -1;  },//反转数组  reverse: function(inline) {    return (inline !== false ? this : this.toArray())._reverse();  },//删除数组中第一个元素并返回这个元素的值  shift: function() {    var result = this[0];    for (var i = 0; i < this.length - 1; i++)      this[i] = this[i + 1];    this.length--;    return result;  },//得到数组的字符串描述例如arr=[1,2,3]-----> "[1,2,3]"  inspect: function() {    return '[' + this.map(Object.inspect).join(', ') + ']';  }});/*========================================================================================*///【Hash】哈希对象var Hash = {//实现枚举接口方法从而使Hash对象也是枚举对象  _each: function(iterator) {    for (key in this) {      var value = this[key];      if (typeof value == 'function') continue;      var pair = [key, value];      pair.key = key;      pair.value = value;      iterator(pair);    }  },//所有键数组  keys: function() {    return this.pluck('key');  },//所有值数组  values: function() {    return this.pluck('value');  },//合并哈希表,键相同就覆盖调用者  merge: function(hash) {    return $H(hash).inject($H(this), function(mergedHash, pair) {      mergedHash[pair.key] = pair.value;      return mergedHash;    });  },//键值对组成查询字符串的形式  toQueryString: function() {    return this.map(function(pair) {      return pair.map(encodeURIComponent).join('=');    }).join('&');  },//获取Hash对象的字符串描述  inspect: function() {    return '#<Hash:{' + this.map(function(pair) {      return pair.map(Object.inspect).join(': ');    }).join(', ') + '}>';  }}/*哈希表不是类而是对象所以不能用new的方法创建,而是用$H()函数  这个方法吧一个对象转换为哈希对象,对象的属性名为key 值为value  可枚举!!*/function $H(object) {  var hash = Object.extend({}, object || {});  Object.extend(hash, Enumerable);  Object.extend(hash, Hash);  return hash;}/*========================================================================================*///【ObjectRange】用于进行指定次数的循环运算,同样继承于枚举接口并实现_each方法//有了这个方法基本上Javascript里面就不用for循环了ObjectRange = Class.create();Object.extend(ObjectRange.prototype, Enumerable);Object.extend(ObjectRange.prototype, {//构造函数同事指定了3个参数的值  initialize: function(start, end, exclusive) {    this.start = start; //其实索引    this.end = end;//结束索引    this.exclusive = exclusive;//表示是否包含结束索引  },  _each: function(iterator) {    var value = this.start;    do {      iterator(value);      value = value.succ();    } while (this.include(value));  },//重写枚举接口的include方法,判断改循环的索引是否包含参数value的指定的值  include: function(value) {    if (value < this.start)      return false;    if (this.exclusive)      return value < this.end;    return value <= this.end;  }});//使用$R()方法快速创建objectRange对象var $R = function(start, end, exclusive) {  return new ObjectRange(start, end, exclusive);}/*========================================================================================*//* 【Ajax模块】/*========================================================================================*///【ajax对象】var Ajax = {//创建浏览器兼容的XMLHttpRequest对象  getTransport: function() {    return Try.these(      function() {return new ActiveXObject('Msxml2.XMLHTTP')},      function() {return new ActiveXObject('Microsoft.XMLHTTP')},      function() {return new XMLHttpRequest()}    ) || false;  },//当前激活的请求数目  activeRequestCount: 0}//【Ajax.Responders对象】Ajax.Responders = {  responders: [],//表示所有响应处理代理  _each: function(iterator) {    this.responders._each(iterator);  },//注册一个响应代理  register: function(responderToAdd) {    if (!this.include(responderToAdd))      this.responders.push(responderToAdd);  },//删除一个响应代理  unregister: function(responderToRemove) {    this.responders = this.responders.without(responderToRemove);  },//分发一个回调函数,让所有半酣callback回调函数事件标识符的响应代理都被调用//传递三个参数最后一个可选表示Json对象  dispatch: function(callback, request, transport, json) {    this.each(function(responder) {      if (responder[callback] && typeof responder[callback] == 'function') {        try {          responder[callback].apply(responder, [request, transport, json]);        } catch (e) {}      }    });  }};Object.extend(Ajax.Responders, Enumerable);//统计当前活动请求的数目Ajax.Responders.register({//开始创建了一个请求  onCreate: function() {    Ajax.activeRequestCount++;  },//请求结束  onComplete: function() {    Ajax.activeRequestCount--;  }});//【Ajax.Base类】进行服务器通信的基类Ajax.Base = function() {};Ajax.Base.prototype = {  setOptions: function(options) {    this.options = {      method:       'post',      asynchronous: true,      parameters:   ''    }    Object.extend(this.options, options || {});  },  responseIsSuccess: function() {    return this.transport.status == undefined        || this.transport.status == 0        || (this.transport.status >= 200 && this.transport.status < 300);  },  responseIsFailure: function() {    return !this.responseIsSuccess();  }}//【Ajax.Request类】用于向服务器端发送请求,封装了XmlHttpRequestAjax.Request = Class.create();Ajax.Request.Events =  ['Uninitialized', 'Loading', 'Loaded', 'Interactive', 'Complete'];Ajax.Request.prototype = Object.extend(new Ajax.Base(), {  initialize: function(url, options) {    this.transport = Ajax.getTransport();    this.setOptions(options);//使用基类方法设置    this.request(url);  },//向指定url发送请求 一般不会显示调用  request: function(url) {    var parameters = this.options.parameters || '';    if (parameters.length > 0) parameters += '&_=';    try {      this.url = url;      if (this.options.method == 'get' && parameters.length > 0)        this.url += (this.url.match(/\?/) ? '&' : '?') + parameters;      Ajax.Responders.dispatch('onCreate', this, this.transport);      this.transport.open(this.options.method, this.url,        this.options.asynchronous);      if (this.options.asynchronous) {        this.transport.onreadystatechange = this.onStateChange.bind(this);        setTimeout((function() {this.respondToReadyState(1)}).bind(this), 10);      }      this.setRequestHeaders();      var body = this.options.postBody ? this.options.postBody : parameters;      this.transport.send(this.options.method == 'post' ? body : null);    } catch (e) {      this.dispatchException(e);    }  },//设置请求的Http头 类内部使用 一般无需显示调用  setRequestHeaders: function() {    var requestHeaders =      ['X-Requested-With', 'XMLHttpRequest',       'X-Prototype-Version', Prototype.Version];    if (this.options.method == 'post') {      requestHeaders.push('Content-type',        'application/x-www-form-urlencoded');      /* Force "Connection: close" for Mozilla browsers to work around       * a bug where XMLHttpReqeuest sends an incorrect Content-length       * header. See Mozilla Bugzilla #246651.       */      if (this.transport.overrideMimeType)        requestHeaders.push('Connection', 'close');    }    if (this.options.requestHeaders)      requestHeaders.push.apply(requestHeaders, this.options.requestHeaders);    for (var i = 0; i < requestHeaders.length; i += 2)      this.transport.setRequestHeader(requestHeaders[i], requestHeaders[i+1]);  },//检测XMLHttpRquest对象的onstatechange事件类内部使用 一般无需显示调用  onStateChange: function() {    var readyState = this.transport.readyState;    if (readyState != 1)      this.respondToReadyState(this.transport.readyState);  },//获取指定的Http头的内容  header: function(name) {    try {      return this.transport.getResponseHeader(name);    } catch (e) {}  },//如果服务器返回了Http头"X-JOSN"则将其作为js执行并返回执行结果  evalJSON: function() {    try {      return eval(this.header('X-JSON'));    } catch (e) {}  },//将XMLHttpRequest返回的responseText作为JS语句执行并返回执行结果  evalResponse: function() {    try {      return eval(this.transport.responseText);    } catch (e) {      this.dispatchException(e);    }  },//处理XMLHttpRequest的readystate属性根据成功或失败调用Options对象中相应的回调函数//同时通知Ajax.Responders中注册的响应处理句柄  respondToReadyState: function(readyState) {    var event = Ajax.Request.Events[readyState];    var transport = this.transport, json = this.evalJSON();    if (event == 'Complete') {      try {        (this.options['on' + this.transport.status]         || this.options['on' + (this.responseIsSuccess() ? 'Success' : 'Failure')]         || Prototype.emptyFunction)(transport, json);      } catch (e) {        this.dispatchException(e);      }      if ((this.header('Content-type') || '').match(/^text\/javascript/i))        this.evalResponse();    }    try {      (this.options['on' + event] || Prototype.emptyFunction)(transport, json);      Ajax.Responders.dispatch('on' + event, this, transport, json);    } catch (e) {      this.dispatchException(e);    }    /* Avoid memory leak in MSIE: clean up the oncomplete event handler */    if (event == 'Complete')      this.transport.onreadystatechange = Prototype.emptyFunction;  },  dispatchException: function(exception) {    (this.options.onException || Prototype.emptyFunction)(this, exception);    Ajax.Responders.dispatch('onException', this, exception);  }});/*========================================================================================*///【Ajax.Updater类】用于将获取的内容填充到指定的容器中去Ajax.Updater = Class.create();Object.extend(Object.extend(Ajax.Updater.prototype, Ajax.Request.prototype), {//重写了构造函数  initialize: function(container, url, options) {    this.containers = {      success: container.success ? $(container.success) : $(container),      failure: container.failure ? $(container.failure) :        (container.success ? null : $(container))    }    this.transport = Ajax.getTransport();    this.setOptions(options);//可以指定evalscripts属性和insertion属性    var onComplete = this.options.onComplete || Prototype.emptyFunction;    this.options.onComplete = (function(transport, object) {      this.updateContent();      onComplete(transport, object);    }).bind(this);    this.request(url);  },  updateContent: function() {    var receiver = this.responseIsSuccess() ?      this.containers.success : this.containers.failure;    var response = this.transport.responseText;    if (!this.options.evalScripts)      response = response.stripScripts();    if (receiver) {      if (this.options.insertion) {        new this.options.insertion(receiver, response);      } else {        Element.update(receiver, response);      }    }    if (this.responseIsSuccess()) {      if (this.onComplete)        setTimeout(this.onComplete.bind(this), 10);    }  }});/*========================================================================================*///【Ajax.PeriodicalUpdater类】用于定时执行服务器异步调用,功能与Updater相同只是有了定时功能Ajax.PeriodicalUpdater = Class.create();Ajax.PeriodicalUpdater.prototype = Object.extend(new Ajax.Base(), {  initialize: function(container, url, options) {    this.setOptions(options);    this.onComplete = this.options.onComplete;//区别就在下面两个属性 频率 衰减参数 指数增长!只要有一次不同旧回复原有频率    this.frequency = (this.options.frequency || 2);    this.decay = (this.options.decay || 1);    this.updater = {};    this.container = container;    this.url = url;    this.start();  },  start: function() {    this.options.onComplete = this.updateComplete.bind(this);    this.onTimerEvent();  },  stop: function() {    this.updater.onComplete = undefined;    clearTimeout(this.timer);    (this.onComplete || Prototype.emptyFunction).apply(this, arguments);  },  updateComplete: function(request) {    if (this.options.decay) {      this.decay = (request.responseText == this.lastText ?        this.decay * this.options.decay : 1);      this.lastText = request.responseText;    }    this.timer = setTimeout(this.onTimerEvent.bind(this),      this.decay * this.frequency * 1000);  },  onTimerEvent: function() {    this.updater = new Ajax.Updater(this.container, this.url, this.options);  }});/*========================================================================================*//*【文档操作的封装】/*========================================================================================*///返回了一个数组包含了所有符合条件的结点的引用document.getElementsByClassName = function(className, parentElement) { //parentElement不指定就在全局查找  var children = ($(parentElement) || document.body).getElementsByTagName('*');  return $A(children).inject([], function(elements, child) {    if (child.className.match(new RegExp("(^|\\s)" + className + "(\\s|$)")))      elements.push(child);    return elements;  });}/*【Element对象】用于对文档结点做一些统一的操作*/if (!window.Element) {  var Element = new Object();}Object.extend(Element, {  visible: function(element) {    return $(element).style.display != 'none';  },//指定结点可见性的切换  toggle: function() {    for (var i = 0; i < arguments.length; i++) {      var element = $(arguments[i]);      Element[Element.visible(element) ? 'hide' : 'show'](element);    }  },  hide: function() {    for (var i = 0; i < arguments.length; i++) {      var element = $(arguments[i]);      element.style.display = 'none';    }  },  show: function() {    for (var i = 0; i < arguments.length; i++) {      var element = $(arguments[i]);      element.style.display = '';    }  },  remove: function(element) {    element = $(element);    element.parentNode.removeChild(element);  },//将html片段填充到element指定的结点中  update: function(element, html) {    $(element).innerHTML = html.stripScripts();    setTimeout(function() {html.evalScripts()}, 10);  },//获得element的绝对高度  getHeight: function(element) {    element = $(element);    return element.offsetHeight;  },  classNames: function(element) {    return new Element.ClassNames(element);  },  hasClassName: function(element, className) {    if (!(element = $(element))) return;    return Element.classNames(element).include(className);  },  addClassName: function(element, className) {    if (!(element = $(element))) return;    return Element.classNames(element).add(className);  },  removeClassName: function(element, className) {    if (!(element = $(element))) return;    return Element.classNames(element).remove(className);  },  // removes whitespace-only text node children  cleanWhitespace: function(element) {    element = $(element);    for (var i = 0; i < element.childNodes.length; i++) {      var node = element.childNodes[i];      if (node.nodeType == 3 && !/\S/.test(node.nodeValue))        Element.remove(node);    }  },  empty: function(element) {    return $(element).innerHTML.match(/^\s*$/);  },//将浏览器的滚动条滚动到指定的结点的位置  scrollTo: function(element) {    element = $(element);    var x = element.x ? element.x : element.offsetLeft,        y = element.y ? element.y : element.offsetTop;    window.scrollTo(x, y);  },//得到element的结点的绝对样式  getStyle: function(element, style) {    element = $(element);    var value = element.style[style.camelize()];    if (!value) {      if (document.defaultView && document.defaultView.getComputedStyle) {        var css = document.defaultView.getComputedStyle(element, null);        value = css ? css.getPropertyValue(style) : null;      } else if (element.currentStyle) {        value = element.currentStyle[style.camelize()];      }    }    if (window.opera && ['left', 'top', 'right', 'bottom'].include(style))      if (Element.getStyle(element, 'position') == 'static') value = 'auto';    return value == 'auto' ? null : value;  },//设置结点样式 var style={background-color:'black',color:'red'} Element.setStyle($('div1'),style)  setStyle: function(element, style) {    element = $(element);    for (name in style)      element.style[name.camelize()] = style[name];  },    //获得结点的宽度高度 该方法无论结点是否可见 都能获得其大小  getDimensions: function(element) {    element = $(element);    if (Element.getStyle(element, 'display') != 'none')      return {width: element.offsetWidth, height: element.offsetHeight};    // All *Width and *Height properties give 0 on elements with display none,    // so enable the element temporarily    var els = element.style;    var originalVisibility = els.visibility;    var originalPosition = els.position;    els.visibility = 'hidden';    els.position = 'absolute';    els.display = '';    var originalWidth = element.clientWidth;    var originalHeight = element.clientHeight;    els.display = 'none';    els.position = originalPosition;    els.visibility = originalVisibility;    return {width: originalWidth, height: originalHeight};  },//相对定位  makePositioned: function(element) {    element = $(element);    var pos = Element.getStyle(element, 'position');    if (pos == 'static' || !pos) {      element._madePositioned = true;      element.style.position = 'relative';      // Opera returns the offset relative to the positioning context, when an      // element is position relative but top and left have not been defined      if (window.opera) {        element.style.top = 0;        element.style.left = 0;      }    }  },//取消相对定位  undoPositioned: function(element) {    element = $(element);    if (element._madePositioned) {      element._madePositioned = undefined;      element.style.position =        element.style.top =        element.style.left =        element.style.bottom =        element.style.right = '';    }  },//使结点隐藏超出的部分 overflow=relative  makeClipping: function(element) {    element = $(element);    if (element._overflow) return;    element._overflow = element.style.overflow;    if ((Element.getStyle(element, 'overflow') || 'visible') != 'hidden')      element.style.overflow = 'hidden';  },  undoClipping: function(element) {    element = $(element);    if (element._overflow) return;    element.style.overflow = element._overflow;    element._overflow = undefined;  }});/*========================================================================================*///Toggle对象是Element.toggle方法的一个快捷用法var Toggle = new Object();Toggle.display = Element.toggle;/*========================================================================================*///【Insertion命名空间】包含了4个类把指定的html片段插入到指定的结点的相应位置上Abstract.Insertion = function(adjacency) {  this.adjacency = adjacency;}Abstract.Insertion.prototype = {  initialize: function(element, content) {    this.element = $(element);    this.content = content.stripScripts();    if (this.adjacency && this.element.insertAdjacentHTML) {      try {        this.element.insertAdjacentHTML(this.adjacency, this.content);      } catch (e) {        if (this.element.tagName.toLowerCase() == 'tbody') {          this.insertContent(this.contentFromAnonymousTable());        } else {          throw e;        }      }    } else {      this.range = this.element.ownerDocument.createRange();      if (this.initializeRange) this.initializeRange();      this.insertContent([this.range.createContextualFragment(this.content)]);    }    setTimeout(function() {content.evalScripts()}, 10);  },  contentFromAnonymousTable: function() {    var div = document.createElement('div');    div.innerHTML = '<table><tbody>' + this.content + '</tbody></table>';    return $A(div.childNodes[0].childNodes[0].childNodes);  }}var Insertion = new Object();Insertion.Before = Class.create();Insertion.Before.prototype = Object.extend(new Abstract.Insertion('beforeBegin'), {  initializeRange: function() {    this.range.setStartBefore(this.element);  },  insertContent: function(fragments) {    fragments.each((function(fragment) {      this.element.parentNode.insertBefore(fragment, this.element);    }).bind(this));  }});Insertion.Top = Class.create();Insertion.Top.prototype = Object.extend(new Abstract.Insertion('afterBegin'), {  initializeRange: function() {    this.range.selectNodeContents(this.element);    this.range.collapse(true);  },  insertContent: function(fragments) {    fragments.reverse(false).each((function(fragment) {      this.element.insertBefore(fragment, this.element.firstChild);    }).bind(this));  }});Insertion.Bottom = Class.create();Insertion.Bottom.prototype = Object.extend(new Abstract.Insertion('beforeEnd'), {  initializeRange: function() {    this.range.selectNodeContents(this.element);    this.range.collapse(this.element);  },  insertContent: function(fragments) {    fragments.each((function(fragment) {      this.element.appendChild(fragment);    }).bind(this));  }});Insertion.After = Class.create();Insertion.After.prototype = Object.extend(new Abstract.Insertion('afterEnd'), {  initializeRange: function() {    this.range.setStartAfter(this.element);  },  insertContent: function(fragments) {    fragments.each((function(fragment) {      this.element.parentNode.insertBefore(fragment,        this.element.nextSibling);    }).bind(this));  }});/*========================================================================================*///【Element.ClassNames】获得一个结点的所有的class名称组成的对象,实现了枚举接口Element.ClassNames = Class.create();Element.ClassNames.prototype = {  initialize: function(element) {    this.element = $(element);  },  _each: function(iterator) {    this.element.className.split(/\s+/).select(function(name) {      return name.length > 0;    })._each(iterator);  },  set: function(className) {    this.element.className = className;  },  add: function(classNameToAdd) {    if (this.include(classNameToAdd)) return;    this.set(this.toArray().concat(classNameToAdd).join(' '));  },  remove: function(classNameToRemove) {    if (!this.include(classNameToRemove)) return;    this.set(this.select(function(className) {      return className != classNameToRemove;    }).join(' '));  },  toString: function() {//获得所有class的字符串表示空格隔开    return this.toArray().join(' ');  }}//表单域对象工具类Object.extend(Element.ClassNames.prototype, Enumerable);var Field = {  clear: function() {    for (var i = 0; i < arguments.length; i++)      $(arguments[i]).value = '';  },  focus: function(element) {    $(element).focus();  },  present: function() {    for (var i = 0; i < arguments.length; i++)      if ($(arguments[i]).value == '') return false;    return true;  },//选中表单域  select: function(element) {    $(element).select();  },//focus + select  activate: function(element) {    element = $(element);    element.focus();    if (element.select)      element.select();  }}/*【Form】表单工具对象*/var Form = {//表单数据序列化  serialize: function(form) {    var elements = Form.getElements($(form));    var queryComponents = new Array();    for (var i = 0; i < elements.length; i++) {      var queryComponent = Form.Element.serialize(elements[i]);      if (queryComponent)        queryComponents.push(queryComponent);    }    return queryComponents.join('&');  },//获取所有表单域按照标记名排列  getElements: function(form) {    form = $(form);    var elements = new Array();    for (tagName in Form.Element.Serializers) {      var tagElements = form.getElementsByTagName(tagName);      for (var j = 0; j < tagElements.length; j++)        elements.push(tagElements[j]);    }    return elements;  },//有一个满足就返回  getInputs: function(form, typeName, name) {    form = $(form);    var inputs = form.getElementsByTagName('input');    if (!typeName && !name)      return inputs;    var matchingInputs = new Array();    for (var i = 0; i < inputs.length; i++) {      var input = inputs[i];      if ((typeName && input.type != typeName) ||          (name && input.name != name))        continue;      matchingInputs.push(input);    }    return matchingInputs;  },//整个表单域禁用  disable: function(form) {    var elements = Form.getElements(form);    for (var i = 0; i < elements.length; i++) {      var element = elements[i];      element.blur();      element.disabled = 'true';    }  },//启用  enable: function(form) {    var elements = Form.getElements(form);    for (var i = 0; i < elements.length; i++) {      var element = elements[i];      element.disabled = '';    }  },//获取第一个可用的表单域  findFirstElement: function(form) {    return Form.getElements(form).find(function(element) {      return element.type != 'hidden' && !element.disabled &&        ['input', 'select', 'textarea'].include(element.tagName.toLowerCase());    });  },//激活第一个表单域  focusFirstElement: function(form) {    Field.activate(Form.findFirstElement(form));  },  reset: function(form) {    $(form).reset();  }}//【Form.Element】 对特定的表单域进行操作Form.Element = {//序列化形成"&name=value"  serialize: function(element) {    element = $(element);    var method = element.tagName.toLowerCase();    var parameter = Form.Element.Serializers[method](element);    if (parameter) {      var key = encodeURIComponent(parameter[0]);      if (key.length == 0) return;      if (parameter[1].constructor != Array)        parameter[1] = [parameter[1]];      return parameter[1].map(function(value) {        return key + '=' + encodeURIComponent(value);      }).join('&');    }  },//获得指定表单域的值  getValue: function(element) {    element = $(element);    var method = element.tagName.toLowerCase();    var parameter = Form.Element.Serializers[method](element);    if (parameter)      return parameter[1];  }}//【Form.Element.Serializers】针对不同的表单域进行序列化Form.Element.Serializers = {//一般用所有的<input>标记的序列化都可以  input: function(element) {    switch (element.type.toLowerCase()) {      case 'submit':      case 'hidden':      case 'password':      case 'text':        return Form.Element.Serializers.textarea(element);      case 'checkbox':      case 'radio':        return Form.Element.Serializers.inputSelector(element);    }    return false;  },  inputSelector: function(element) {    if (element.checked)      return [element.name, element.value];  },  textarea: function(element) {    return [element.name, element.value];  },  select: function(element) {    return Form.Element.Serializers[element.type == 'select-one' ?      'selectOne' : 'selectMany'](element);  },  selectOne: function(element) {    var value = '', opt, index = element.selectedIndex;    if (index >= 0) {      opt = element.options[index];      value = opt.value;      if (!value && !('value' in opt))        value = opt.text;    }    return [element.name, value];  },  selectMany: function(element) {    var value = new Array();    for (var i = 0; i < element.length; i++) {      var opt = element.options[i];      if (opt.selected) {        var optValue = opt.value;        if (!optValue && !('value' in opt))          optValue = opt.text;        value.push(optValue);      }    }    return [element.name, value];  }}//【获得表单域的值】var $F = Form.Element.getValue;/*========================================================================================*//*【Observer模式框架】 观察对象仅仅针对表单和表单域*//*========================================================================================*/Abstract.TimedObserver = function() {}//定义了基于定时器的观察模式基类后面的类都继承了这个类Abstract.TimedObserver.prototype = {  initialize: function(element, frequency, callback) {    this.frequency = frequency;//观察频率    this.element   = $(element);//被观察的对象    this.callback  = callback;//回调函数接受参数 被观察对象自身和触发事件时的值    this.lastValue = this.getValue();//这是观察的值!!    this.registerCallback();  },//注册回调函数  registerCallback: function() {    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);  },//每一个时间片触发一次该事件  onTimerEvent: function() {    var value = this.getValue();    if (this.lastValue != value) {      this.callback(this.element, value);      this.lastValue = value;    }  }}//【Form.Element.Observer类】实现了getvalue方法Form.Element.Observer = Class.create();Form.Element.Observer.prototype = Object.extend(new Abstract.TimedObserver(), {  getValue: function() {    return Form.Element.getValue(this.element);  }});//【Form.Observer类】实现了getvalue方法,只要有一个表单域发生变化就会触发回调Form.Observer = Class.create();Form.Observer.prototype = Object.extend(new Abstract.TimedObserver(), {  getValue: function() {    return Form.serialize(this.element);  }});//【Abstract.EventObserver 类】基于事件的Oberver模式的基类 后面的具体类都继承这个类Abstract.EventObserver = function() {}Abstract.EventObserver.prototype = {  initialize: function(element, callback) {    this.element  = $(element);    this.callback = callback;    this.lastValue = this.getValue();    if (this.element.tagName.toLowerCase() == 'form')      this.registerFormCallbacks();    else      this.registerCallback(this.element);  },//每次发生事件时被调用 内部调用 无需显示调用  onElementEvent: function() {    var value = this.getValue();    if (this.lastValue != value) {      this.callback(this.element, value);      this.lastValue = value;    }  },//注册表表单域事件  registerFormCallbacks: function() {    var elements = Form.getElements(this.element);    for (var i = 0; i < elements.length; i++)      this.registerCallback(elements[i]);  },  registerCallback: function(element) {    if (element.type) {      switch (element.type.toLowerCase()) {        case 'checkbox':        case 'radio':          Event.observe(element, 'click', this.onElementEvent.bind(this));          break;        case 'password':        case 'text':        case 'textarea':        case 'select-one':        case 'select-multiple':          Event.observe(element, 'change', this.onElementEvent.bind(this));          break;      }    }  }}//【Form.Element.EventObserver】Form.Element.EventObserver = Class.create();Form.Element.EventObserver.prototype = Object.extend(new Abstract.EventObserver(), {  getValue: function() {    return Form.Element.getValue(this.element);  }});//【Form.EventObserver】Form.EventObserver = Class.create();Form.EventObserver.prototype = Object.extend(new Abstract.EventObserver(), {  getValue: function() {    return Form.serialize(this.element);  }});/*========================================================================================*//*【事件处理:对Event对象的扩展】对javascript事件处理机制进行封装*//*========================================================================================*/if (!window.Event) {  var Event = new Object();}Object.extend(Event, {  KEY_BACKSPACE: 8,  KEY_TAB:       9,  KEY_RETURN:   13,  KEY_ESC:      27,  KEY_LEFT:     37,  KEY_UP:       38,  KEY_RIGHT:    39,  KEY_DOWN:     40,  KEY_DELETE:   46,//获取触发事件的对象  element: function(event) {    return event.target || event.srcElement;  },  isLeftClick: function(event) {    return (((event.which) && (event.which == 1)) ||            ((event.button) && (event.button == 1)));  },  pointerX: function(event) {    return event.pageX || (event.clientX +      (document.documentElement.scrollLeft || document.body.scrollLeft));  },  pointerY: function(event) {    return event.pageY || (event.clientY +      (document.documentElement.scrollTop || document.body.scrollTop));  },//停止事件的传递  stop: function(event) {    if (event.preventDefault) {      event.preventDefault();      event.stopPropagation();    } else {      event.returnValue = false;      event.cancelBubble = true;    }  },  // find the first node with the given tagName, starting from the  // node the event was triggered on; traverses the DOM upwards  findElement: function(event, tagName) {    var element = Event.element(event);    while (element.parentNode && (!element.tagName ||        (element.tagName.toUpperCase() != tagName.toUpperCase())))      element = element.parentNode;    return element;  },  observers: false,  _observeAndCache: function(element, name, observer, useCapture) {    if (!this.observers) this.observers = [];    if (element.addEventListener) {      this.observers.push([element, name, observer, useCapture]);      element.addEventListener(name, observer, useCapture);    } else if (element.attachEvent) {      this.observers.push([element, name, observer, useCapture]);      element.attachEvent('on' + name, observer);    }  },//删除所有通过Event.observers绑定的事件  unloadCache: function() {    if (!Event.observers) return;    for (var i = 0; i < Event.observers.length; i++) {      Event.stopObserving.apply(this, Event.observers[i]);      Event.observers[i][0] = null;    }    Event.observers = false;  },//绑定一个事件  observe: function(element, name, observer, useCapture) {    var element = $(element);    useCapture = useCapture || false;    if (name == 'keypress' &&        (navigator.appVersion.match(/Konqueror|Safari|KHTML/)        || element.attachEvent))      name = 'keydown';    this._observeAndCache(element, name, observer, useCapture);  },//取消事件绑定  stopObserving: function(element, name, observer, useCapture) {    var element = $(element);    useCapture = useCapture || false;    if (name == 'keypress' &&        (navigator.appVersion.match(/Konqueror|Safari|KHTML/)        || element.detachEvent))      name = 'keydown';    if (element.removeEventListener) {      element.removeEventListener(name, observer, useCapture);    } else if (element.detachEvent) {      element.detachEvent('on' + name, observer);    }  }});//【结点的位置处理:Position对象】/* prevent memory leaks in IE */Event.observe(window, 'unload', Event.unloadCache, false);var Position = {  // set to true if needed, warning: firefox performance problems  // NOT neeeded for page scrolling, only if draggable contained in  // scrollable elements  includeScrollOffsets: false,  // must be called before calling withinIncludingScrolloffset, every time the  // page is scrolled用于计算滚动条的位置信息  prepare: function() {    this.deltaX =  window.pageXOffset                || document.documentElement.scrollLeft                || document.body.scrollLeft                || 0;    this.deltaY =  window.pageYOffset                || document.documentElement.scrollTop                || document.body.scrollTop                || 0;  },//计算节点的绝对滚动位置返回包含两个元素的数组到文档左侧 顶部的距离  realOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.scrollTop  || 0;      valueL += element.scrollLeft || 0;      element = element.parentNode;    } while (element);    return [valueL, valueT];  },//计算结点相对于文档的绝对滚动位置,返回包含两个元素的数组到文档左侧 顶部的距离  cumulativeOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      element = element.offsetParent;    } while (element);    return [valueL, valueT];  },//相对位置  positionedOffset: function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      element = element.offsetParent;      if (element) {        p = Element.getStyle(element, 'position');        if (p == 'relative' || p == 'absolute') break;      }    } while (element);    return [valueL, valueT];  },  offsetParent: function(element) {    if (element.offsetParent) return element.offsetParent;    if (element == document.body) return element;    while ((element = element.parentNode) && element != document.body)      if (Element.getStyle(element, 'position') != 'static')        return element;    return document.body;  },  // caches x/y coordinate pair to use with overlap是否在element内  within: function(element, x, y) {    if (this.includeScrollOffsets)      return this.withinIncludingScrolloffsets(element, x, y);    this.xcomp = x;    this.ycomp = y;    this.offset = this.cumulativeOffset(element);    return (y >= this.offset[1] &&            y <  this.offset[1] + element.offsetHeight &&            x >= this.offset[0] &&            x <  this.offset[0] + element.offsetWidth);  },  withinIncludingScrolloffsets: function(element, x, y) {    var offsetcache = this.realOffset(element);    this.xcomp = x + offsetcache[0] - this.deltaX;    this.ycomp = y + offsetcache[1] - this.deltaY;    this.offset = this.cumulativeOffset(element);    return (this.ycomp >= this.offset[1] &&            this.ycomp <  this.offset[1] + element.offsetHeight &&            this.xcomp >= this.offset[0] &&            this.xcomp <  this.offset[0] + element.offsetWidth);  },  // within must be called directly before  overlap: function(mode, element) {    if (!mode) return 0;    if (mode == 'vertical')      return ((this.offset[1] + element.offsetHeight) - this.ycomp) /        element.offsetHeight;    if (mode == 'horizontal')      return ((this.offset[0] + element.offsetWidth) - this.xcomp) /        element.offsetWidth;  },//克隆结点 常用于拖放  clone: function(source, target) {    source = $(source);    target = $(target);    target.style.position = 'absolute';    var offsets = this.cumulativeOffset(source);    target.style.top    = offsets[1] + 'px';    target.style.left   = offsets[0] + 'px';    target.style.width  = source.offsetWidth + 'px';    target.style.height = source.offsetHeight + 'px';  },  page: function(forElement) {    var valueT = 0, valueL = 0;    var element = forElement;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      // Safari fix      if (element.offsetParent==document.body)        if (Element.getStyle(element,'position')=='absolute') break;    } while (element = element.offsetParent);    element = forElement;    do {      valueT -= element.scrollTop  || 0;      valueL -= element.scrollLeft || 0;    } while (element = element.parentNode);    return [valueL, valueT];  },  clone: function(source, target) {    var options = Object.extend({      setLeft:    true,      setTop:     true,      setWidth:   true,      setHeight:  true,      offsetTop:  0,      offsetLeft: 0    }, arguments[2] || {})    // find page position of source    source = $(source);    var p = Position.page(source);    // find coordinate system to use    target = $(target);    var delta = [0, 0];    var parent = null;    // delta [0,0] will do fine with position: fixed elements,    // position:absolute needs offsetParent deltas    if (Element.getStyle(target,'position') == 'absolute') {      parent = Position.offsetParent(target);      delta = Position.page(parent);    }    // correct by body offsets (fixes Safari)    if (parent == document.body) {      delta[0] -= document.body.offsetLeft;      delta[1] -= document.body.offsetTop;    }    // set position    if(options.setLeft)   target.style.left  = (p[0] - delta[0] + options.offsetLeft) + 'px';    if(options.setTop)    target.style.top   = (p[1] - delta[1] + options.offsetTop) + 'px';    if(options.setWidth)  target.style.width = source.offsetWidth + 'px';    if(options.setHeight) target.style.height = source.offsetHeight + 'px';  },//绝对定位  absolutize: function(element) {    element = $(element);    if (element.style.position == 'absolute') return;    Position.prepare();    var offsets = Position.positionedOffset(element);    var top     = offsets[1];    var left    = offsets[0];    var width   = element.clientWidth;    var height  = element.clientHeight;    element._originalLeft   = left - parseFloat(element.style.left  || 0);    element._originalTop    = top  - parseFloat(element.style.top || 0);    element._originalWidth  = element.style.width;    element._originalHeight = element.style.height;    element.style.position = 'absolute';    element.style.top    = top + 'px';;    element.style.left   = left + 'px';;    element.style.width  = width + 'px';;    element.style.height = height + 'px';;  },//相对定位  relativize: function(element) {    element = $(element);    if (element.style.position == 'relative') return;    Position.prepare();    element.style.position = 'relative';    var top  = parseFloat(element.style.top  || 0) - (element._originalTop || 0);    var left = parseFloat(element.style.left || 0) - (element._originalLeft || 0);    element.style.top    = top + 'px';    element.style.left   = left + 'px';    element.style.height = element._originalHeight;    element.style.width  = element._originalWidth;  }}// Safari returns margins on body which is incorrect if the child is absolutely// positioned.  For performance reasons, redefine Position.cumulativeOffset for// KHTML/WebKit only.if (/Konqueror|Safari|KHTML/.test(navigator.userAgent)) {  Position.cumulativeOffset = function(element) {    var valueT = 0, valueL = 0;    do {      valueT += element.offsetTop  || 0;      valueL += element.offsetLeft || 0;      if (element.offsetParent == document.body)        if (Element.getStyle(element, 'position') == 'absolute') break;      element = element.offsetParent;    } while (element);    return [valueL, valueT];  }}//--------->完成

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