javascript 怎么判断刷新，关闭IE，关闭IE的选项卡

javascript 如何判断刷新，关闭IE，关闭IE的选项卡
javascript 如何判断刷新，关闭IE，关闭IE的选项卡

------解决方案--------------------
window.onunload=function(){ alert("窗口或浏览器被关闭"); }
------解决方案--------------------
Code:
<html>
<script language="javascript"> 
window.onbeforeunload = function() //author: forefront 
{ 
var n = window.event.screenX - window.screenLeft; 
var b = n > document.documentElement.scrollWidth-20; 
if(b && window.event.clientY < 0 || window.event.altKey) 
{ 
window.event.returnValue = ""; 
alert('close');
} 
} 
</script>