var pop = null;



function popdown() {

  if (pop && !pop.closed) pop.close();

}



function popup(obj,w,h) {

  var url = (obj.getAttribute) ? obj.getAttribute('href') : obj.href;

  if (!url) return true;

  w = (w) ? w += 20 : 150;  // 150px*150px is the default size

  h = (h) ? h += 25 : 150;

  var args = 'width='+w+',height='+h+',status=0,menubar=0,scrollbars=1,resizable=1';

  popdown();

  pop = window.open(url,'',args);

  return (pop) ? false : true;

}



window.onunload = popdown;

window.onfocus = popdown;