function refresh_login() {
var xmlHttpLoginCheck;
 	try{
   		xmlHttpLoginCheck=new XMLHttpRequest();
    }catch (e){
   		try{
      		xmlHttpLoginCheck=new ActiveXObject("Msxml2.XMLHTTP");
      	}catch (e){
			try{
         		xmlHttpLoginCheck=new ActiveXObject("Microsoft.XMLHTTP");
         	}catch (e){
         		alert("Your browser does not support AJAX! ");
         		return false;
         	}
		}
    }	
	xmlHttpLoginCheck.onreadystatechange=function() {
		if(xmlHttpLoginCheck.readyState==4){
			if(xmlHttpLoginCheck.responseText == 0) {
				location.href = "http://"+document.domain;
			}			
      	}
    }
    var url = "./window/lib/xmlHttpCheckLogin.php";
	xmlHttpLoginCheck.open("GET",url,true);	
    xmlHttpLoginCheck.send(null);
}