function GetXMLHttp() {  
if(navigator.appName == "Microsoft Internet Explorer") {  
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");  
}  
else {  
xmlHttp = new XMLHttpRequest();  
}  
return xmlHttp;  
}  
  
var xmlRequest = GetXMLHttp();  

var xmlhttp = getXmlHttpRequest();
function getXmlHttpRequest(){
        if(window.XMLHttpRequest){
                return new XMLHttpRequest();
        }else if(window.ActiveXObject){
                try{
                        return new ActiveXObject("Msxml2.XMLHTTP");
                }catch (e){
                        try{
                                return new ActiveXObject("Microsoft.XMLHTTP");
                        }
                        catch (e){}
                }
        }
}