Popup in center of screen

[WALoeIII]

What do I need to add to my code so my popup shows up in the middle of the screen?

[KodeKrash]

<script type="text/javascript">

	var intWidth = 300;
	var intHeight = 300;
	var intLeft = (screen.availWidth / 2) - (intWidth / 2 );
	var intTop = (screen.availHeight / 2) - (intHeight / 2 );
	var strAttrib = 'width=' + intWidth + ',height=' + intHeight + ',top=' + intTop + ',left=' + intLeft;
	var objWin = window.open ('http://www.yahoo.com', 'MyWindow', strAttrib);

</script>

You can see a demo at InteliDev - PopUp Demo.