var pop = null;

function popup(obj,w,h) {
  if (pop && !pop.closed) {
    pop.close();
  }
  else
  {
  var url = (obj.getAttribute) ? obj.getAttribute('href') : obj.href;
  if (!url) return true;
  var h=295;
  var w=480;
  var winl = (screen.width-w)/2;
  var wint = (screen.height-h)/2;
  var settings  ='height='+h+',';
      settings +='width='+w+',';
      settings +='top='+wint+',';
      settings +='left='+winl+',';
      settings +='scrollbars='+scroll+',';
      settings +='resizable=no';
 	pop = window.open(url,'',settings); 

  return (pop) ? false : true;
  }
  var url = (obj.getAttribute) ? obj.getAttribute('href') : obj.href;
  if (!url) return true;
  var h=295;
  var w=480;
  var winl = (screen.width-w)/2;
  var wint = (screen.height-h)/2;
  var settings  ='height='+h+',';
      settings +='width='+w+',';
      settings +='top='+wint+',';
      settings +='left='+winl+',';
      settings +='scrollbars='+scroll+',';
      settings +='resizable=no';
 	pop = window.open(url,'',settings); 

  return (pop) ? false : true;
}