you could take it a step further and try something like this:
the function will display a popup and centre the window according to any screen resolution.
var wndhandle=null;
function openwindow(url,height,width)
{
var screenw,screenh,PosX,PosY,openwin
screenw=window.screen.width;screenh=window.screen.height;
PosX=parseInt((screenw-width)/2);PosY=parseInt((screenh-height)/2);
openwin=window.open;
if(wndhandle!=null)
{
wndhandle.close();
wndhandle=null;
}
else {
wndhandle=null;
wndhandle=openwin(url,null,"status=no,toolbars=no,scrollbars=yes,height="+height+",width="+width+",top="+PosY+",left="+PosX);
wndhandle.focus();
}
}
Hope this helps you out or anyone else!