centret popup!

jeg bruger denne: <script language="JavaScript">
<!--

var w = 350, h = 324;
if (document.all || document.layers) {
  w = screen.availWidth;
  h = screen.availHeight;
}
var popW = 350, popH = 324;
var leftPos = (w-popW)/2, topPos = (h-popH)/2;

//-->
</script>

og denne til linket:
<a href="#" onclick="window.open('http://www.jubii.dk','popup','width=' + popW + ',height=' + popH + ',top=' + topPos + ',left=' + leftPos);return false">klik her...</a>