function CreateXMLHttp()
 {
  xmlHttp = false;
  if(typeof XMLHttpRequest != 'undefined')
  {
   var xmlHttp = new XMLHttpRequest();
   return xmlHttp;
  }else if(window.ActiveXObject)
  {  
   var IEXMLHttpVersion = ["MSXML2.XMLHttp.4.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp","Microsoft.XMLHttp"];
   //for Microsoft Internet Explorer
   for(var i= 0 ;i < IEXMLHttpVersion.length; i++)
   {
    try
    {
       var xmlHttp = new ActiveXObject(IEXMLHttpVersion[i]);
       return xmlHttp;
    }catch(e)
    {
     //Do nothing
    }
   }
   }else
   {
    throw new Error("XMLHttp object could be created.");
   }
 }
 xmlHttp = CreateXMLHttp();
 xmlHttp.setRequestHeader("Content-Type","text/xml");
 xmlHttp.setRequestHeader("Content-Type","gb2312");