close window warning

[BrutusUnix]

I'm trying to get a script to work where if the browser is closed or they leave this site. They get a conf message. (Are you sure you want to leave, Y/N)

             $hdisplay .= "<script language='javascript'>\n";
	$hdisplay .= "function onFeforeUnloadAction(){\n";
	$hdisplay .= "var flag\n";
	$hdisplay .= "var mesg ='You are closing the window. do you want to continue. Click Ok to close or click Cancel to stay back';\n";
	$hdisplay .= "return mesg;\n";
	$hdisplay .= "}\n";
	$hdisplay .= "window.onbeforeunload = function(){if((window.event.clientX<0) || (window.event.clientY<0)){ return onBeforeUnloadAction();}\n";
	$hdisplay .= "</script>\n";

[moritana]

well, technically there's the onunload event (reference: http://www.w3schools.com/jsref/event_onunload.asp )
but at least for me, it doesnt work when you close the page, but works when you press on a link to leave the page.