1 function Ajax(recvType){   2     var aj=new Object();   3     aj.recvType=recvType ? recvType.toUpperCase() : 'HTML' //HTML XML   4     aj.targetUrl='';   5     aj.sendString='';   6     aj.resultHandle=null;   7     aj.createXMLHttpRequest=function(){   8     var request=false;     9     //window对象中有XMLHttpRequest存在就是非IE，包括（IE7，IE8）  10     if(window.XMLHttpRequest){  11         request=new XMLHttpRequest();  12         if(request.overrideMimeType){  13             request.overrideMimeType("text/xml");  14         }  15     //window对象中有ActiveXObject属性存在就是IE  16     }else if(window.ActiveXObject){  17         var versions=['Microsoft.XMLHTTP', 'MSXML.XMLHTTP', 'Msxml2.XMLHTTP.7.0','Msxml2.XMLHTTP.6.0','Msxml2.XMLHTTP.5.0', 'Msxml2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];  18         for(var i=0; i