var win = null;

function popCenter(theURL, winName, w, h)
{
  var fromLeft = 0;
  var fromTop = 0;
	if (window.screen)
  {
    var fromLeft = ((screen.availWidth - w - 10) / 2);
    var fromTop = ((screen.availHeight - h - 30) / 2);
  }
  var settings = 'width=' + w + ',height=' + h + ',left='
               + fromLeft + ',top=' + fromTop + ',location,status,resizable,scrollbars';
  win = window.open(theURL, winName, settings);
  if (window.focus)
    win.focus();
  return false;
}