function popup(url, w, h)
{
  var iMyWidth;
  var iMyHeight;
  
  //half the screen width minus half the new window width
  iMyWidth = (window.screen.width/2) - (w/2);
  //half the screen height minus half the new window height
  iMyHeight = (window.screen.height/2) - (h/2);

  winpops=window.open(url, "", "width=" + w + ",height=" + h + ",left=" + iMyWidth + ",top=" + iMyHeight + ",screenX=" + iMyWidth + ",screenY=" + iMyHeight +",resizable=no")
}