text: var ajaxpool = {
      _objPool: [],
      _getInstance: function (){
          for (var i = 0; i < this._objPool.length; i ++){
              if (this._objPool[i].readyState == 0 || this._objPool[i].readyState == 4){
                  return this._objPool[i];
              }
          }
          this._objPool[this._objPool.length] = this._createObj();
          return this._objPool[this._objPool.length - 1];
      },
      _createObj: function (){
          if (window.XMLHttpRequest){
              var objXMLHttp = new XMLHttpRequest();
          }else{
              var MSXML = ['MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP', 'Microsoft.XMLHTTP'];
              for(var n = 0; n < MSXML.length; n ++){
                  try{
                      var objXMLHttp = new ActiveXObject(MSXML[n]);
                      break;
                  }catch(e){
                  }
              }
           }
          if (objXMLHttp.readyState == null){
              objXMLHttp.readyState = 0;
              objXMLHttp.addEventListener("load", function (){
                      objXMLHttp.readyState = 4;
                      if (typeof objXMLHttp.onreadystatechange == "function"){
                          objXMLHttp.onreadystatechange();
                      }
                  },  false);
          }
          return objXMLHttp;
      },
  	sendReq: function ( url, callback, cbparam, ret ) {
          var objXMLHttp = this._getInstance();
          with(objXMLHttp){
              try{
                  if (url.indexOf("?") > 0){
                      url += "&randnum=" + Math.random();
                  }else{
                      url += "?randnum=" + Math.random();
                  }
                  open( "GET", url, true );
                  setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
                  send(null);
                  
                  if( callback ){
  					onreadystatechange = function () {
  	                    if (objXMLHttp.readyState == 4 && (objXMLHttp.status == 200 || objXMLHttp.status == 304)){
  	                        ret == "xml"? callback( objXMLHttp.responseXML, cbparam ) : callback( objXMLHttp.responseText, cbparam );
  	                    }
  	                }
                  }
              }catch(e){
                  alert(e);
              }
          }
      },
      postReq: function ( url, param, callback, cbparam, ret ) {
          var objXMLHttp = this._getInstance();
          with(objXMLHttp){
              try{
                  if ( param==null || param.length == 0){
                      param += "randnum=" + Math.random();
                  }else{
                      param += "&randnum=" + Math.random();
                  }
                  open( "POST", url, true );
                  setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
                  send( param );
                  
                  if( callback ){
  	                onreadystatechange = function () {
  	                    if (objXMLHttp.readyState == 4 && (objXMLHttp.status == 200 || objXMLHttp.status == 304)){
  							ret == "xml"? callback( objXMLHttp.responseXML, cbparam ) : callback( objXMLHttp.responseText, cbparam );
  	                    }
  	                }
                  }
              }catch(e){
                  alert(e);
              }
          }
      }
  };