[Javascript] positioning: window.open()

[Tom Churm]

hi,

i usually use this code to open a new "pop-up window":

<script language="JavaScript">
<!--
function openHelpWindow () {
  helpWindow = window.open ("popup.html", "MyWindow", 

"menu=no,toolbar=no,location=no,scrollbars=no,width=800,height=600,res

izable=no");
  helpWindow.moveTo((screen.width-420)/2, (screen.height-310)/2);
  helpWindow.focus();
}
// -->
</script>

i've found that there are errors when an Absolute URL is used, ie: 

when the URL for "popup.html" is something like 

"http://someserver.com/popup.html".  since i frequently need to center 

or position pop-ups, i need to find an alternative.

i saw somewhere coding that uses something like top=100; left=200; to 

position a new window, but cannot find any references to this.

any suggestions would be greatly appreciated.

thanks,

tom