var lastwindow=null;
function WinOpen(page, width, height) {
  if (lastwindow != null) lastwindow.close();
	lastwindow = this.open(page,'help','width='+width+',height='+height+',left=0,top=0,toolbar=no,menubar=no,location=no,scrollbars=yes,resizable=yes,directories=no,status=no');
}