// JScript 文件
var x=0; 
function myRefresh() 
{ 
var httpRequest = new ActiveXObject("microsoft.xmlhttp"); 
httpRequest.open("GET", "test.html", false); 
httpRequest.send(null); 
x++; 
if(x<60) //60次，也就是Session真正的过期时间是30分钟 
{ 
setTimeout("myRefresh()",30*1000); //30秒 
} 
} 
myRefresh();

// window.onbeforeunload=function() 
//{ 
//if (event.clientX>document.body.clientWidth && event.clientY<0||event.altKey){ 
//window.open("logout.aspx"); 
//}
//}