var pop = null;

function popdown()
  {
  if((pop)&&(!pop.closed))
	{
    pop.close();
	pop=null;
	}
  }

function popup(obj,w,h)
  {
  var url=(obj.getAttribute)?obj.getAttribute('href'):obj.href;
  if(!url)
    return(true);
  w=(w)?w+=20:864;  // 150px*150px is the default size
  h=(h)?h+=25:714;
  var args='width='+w+',height='+h+',resizable=no,scrollbars=no';
  popdown();
  pop=window.open(url,'',args);
  return((pop)?false:true);
  }

window.onunload = popdown;
window.onfocus = popdown;
window.onfocus = popdown;