function close_up(file, w_width, w_height)
 {
  if (screen)
   {
     leftPos = (screen.width - w_width)/2
     topPos  = (screen.height - w_height)/2
   }

  newWindow = window.open(file, 'newWin', 'toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width='+w_width+',height='+w_height+',left='+leftPos+',top='+topPos);
  newWindow.focus();
 }