function wopen(url, name, w, h)
{
// Fudge factors for window decoration space.
 // In my tests these work well on all platforms & browsers.
w += 36;
h += 125;
wleft = (screen.width - w) / 2;
wtop = (screen.height - h) / 2;
 var win = window.open(url,
  name,
  'width=' + w + ', height=' + h + ', ' +
  'left=' + wleft + ', top=' + wtop + ', ' +
  'location=no, menubar=no, ' +
  'status=no, toolbar=no, scrollbars=no, resizable=no');
 win.resizeTo(w, h);
 win.moveTo(wleft, wtop);
 win.focus();
}