/*  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S   
var 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XmlHttpRequest   
Ajax.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