Javascript capture ie close button event

Code
<Script language = "JavaScript">
Window. onbeforeunload = function ()
{
VaR n = Window. event. screenx-window. screenleft;
VaR B = n> document.doc umentelement. scrollWidth-20;
If (B & window. event. clienty <0 | window. event. altkey)
{
Alert ("Closing the page! ");
}
}
</SCRIPT>

 

The above code can capture the events of clicking the close button of IE and ALT + F4. However, if you right-click the title bar or right-click in the taskbar and select the close button, no