/*
* XMLHttpRequest
*
*/
var HttpRequest = function (url){
    this.XMLHttp=getXMLHttpRequest();
    this.params= "";
    this.url=url;
}
/**
 * 设置远程地址
 */
HttpRequest.prototype.SetURL    =   function(url){
    this.url=url;
}
/**
 * 添加参数
 */
HttpRequest.prototype.AddParam  =   function(name, value){
    if(this.params.length>0)
        this.params+="&";
    this.params+=name+"="+encodeURIComponent(value);
}
/**
 * 发送请求
 */
HttpRequest.prototype.Send  =    function(method){
    var path=this.url;
    if(path.indexOf("?")<0)
        path+="?";
    path+=this.params;
    this.XMLHttp.open(method, path, false);
    this.XMLHttp.setRequestHeader("Content-Type","text/html; charset=UTF-8");
    this.XMLHttp.send();
    return (this.XMLHttp.status==200);
}
/**
 * Get模式调用
 */
HttpRequest.prototype.Get=      function(){
    if(this.Send("GET"))
    return this.XMLHttp.responseText;
    else
    return null;
}


  // 发送请求(方法[post,get], 地址, 数据, 回调函数)
  SendReq: function (method, url, data, callback,id)
  {
      var objXMLHttp = this._getInstance();
      with(objXMLHttp)
      {
          try
          {
              // 加随机数防止缓存
              if (url.indexOf("?") > 0)
              {
                  url += "&randnum=" + Math.random();
              }
              else
              {
                  url += "?randnum=" + Math.random();
              }
              open(method, url, true);
              // 设定请求编码方式
              setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
              send(data);
              onreadystatechange = function ()
              {
                  if (objXMLHttp.readyState == 4 && (objXMLHttp.status == 200 || objXMLHttp.status == 304))
                  {
                      callback(objXMLHttp,id);
                  }
              }
          }
          catch(e)
          {
              alert(e);
          }
      }
  }





function getXMLHttpRequest(){
  http_request = false;
  //开始初始化XMLHttpRequest对象
  if (window.XMLHttpRequest) { //Mozilla 浏览器，IE7
    http_request = new XMLHttpRequest();
      if (http_request.overrideMimeType) {//设置MiME类别
        http_request.overrideMimeType('text/xml');
      }
  } else if (window.ActiveXObject) { // IE6浏览器
    try {
      http_request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {}
    }
  }

  if (!http_request) { // 异常，创建对象实例失败
    window.alert("不能创建XMLHttpRequest对象实例.");
    return null;
  }
//  http_request.setRequestHeader("Content-Type","text/html; charset=UTF-8");
  return http_request;
}

function sendRequest(http_request,url,handler) {//初始化、指定处理函数、发送请求的函数
  http_request.onreadystatechange = handler;
  // 确定发送请求的方式和URL以及是否同步执行下段代码
  //http_request.setHeader("Cache-Control", "no-cache, must-revalidate");
  http_request.open("post", url, true);
  http_request.send(null);
}