FF兼容问题

Question

window.onbeforeunload = function(e)
    {
        e = e || event;
        alert(e);
        var x = e.clientX;  
        var y = e.clientY;  
        alert(x);
        alert(y);
        
        var n = e.screenX - window.screenLeft;      
        var b = n > document.documentElement.scrollWidth-20;      
        if(b && e.clientY < 0 || e.altKey)      
        {      
            alert("是关闭而非刷新");      
            e.returnValue = "是否关闭？";   
        }
        else
        {   
          alert("是刷新而非关闭");      
        }      
    }
FF下完全无效 求解

Answer 1

FF alert x y 全部都是 u

Answer 2

http://topic.csdn.net/u/20080912/16/2177e2ab-c1dd-4d59-8ea3-adf32fa46f22.html

Answer 3

e.clientX，e.clientY只有在鼠标事件中才有效