var Screen=screen.width+"x"+screen.height;
function linkCSS(path){
if(!path) path="";
var date=new Date();
date=date.valueOf();
var xhr_object = null; 
if(window.XMLHttpRequest) // Firefox 
xhr_object = new XMLHttpRequest(); 
else if(window.ActiveXObject) // Internet Explorer 
xhr_object = new ActiveXObject("Microsoft.XMLHTTP"); 
var url=path+"updateSession.inc.php?date="+date;
xhr_object.open("POST",url, true); 
xhr_object.onreadystatechange = function (){ 
   if(xhr_object.readyState == 4 && xhr_object.status==200) {
//alert(xhr_object.responseText);
   }
}
var data = "Screen="+Screen+"&session="+session;
xhr_object.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhr_object.send(data); 

return document.write("<link rel=stylesheet type=text/css href="+path+"default.css?Screen="+Screen+">");
}