function showPopup(url,top) {
  $('#advert').hide();
  $('#popupmaindiv').css('margin-top',top+'px');

  $('#popupexternalcontent').load(url);

  $('#popupbg').fadeTo('fast',0.8, function() {
    $('#popupmaindiv').slideDown('fast');
  });
  
  _gaq.push(['_trackPageview', url]);

}

function closePopup() {
   $('#advert').show();
  $('#popupbg').fadeOut('fast',0);
  $('#popupmaindiv').fadeOut('fast');
}