js监控浏览器封闭

js监控浏览器关闭

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
 <HEAD>
  <TITLE> New Document </TITLE>
  <META NAME="Generator" CONTENT="EditPlus">
  <META NAME="Author" CONTENT="">
  <META NAME="Keywords" CONTENT="">
  <META NAME="Description" CONTENT="">
 </HEAD>
<script type="text/javascript">  
<!--    
    window.onbeforeunload = onbeforeunload_handler;  
    window.onunload = onunload_handler;  
    function onbeforeunload_handler(){  
        var n = window.event.screenX - window.screenLeft;   
              var b = n > document.documentElement.scrollWidth-20;   
              if(b && window.event.clientY < 0 || window.event.altKey)   
              {   
                     alert("是关闭而非刷新");   
                     window.event.returnValue = ""; //这里可以放置你想做的操作代码   
              }   
 
    }  
      
    function onunload_handler(){  
        var warning="谢谢光临";  
        alert(warning);  
    }  
// -->  
</script>  
 <BODY>
 
 </BODY>
</HTML>