//http://www.w3schools.com/ajax/ajax_responsexml.asp
function GetXmlHttpObject(){
	var xmlHttp=null;
	try{
 	 // Firefox, Opera 8.0+, Safari
  		xmlHttp=new XMLHttpRequest();
 	}
	catch (e)
  	{
 	 // Internet Explorer
  		try{
    		xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    	}
 	 	catch (e){
			xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
    	}
  	}
	return xmlHttp;
}