function log()
{
  bug = new Image();
  bug.src = '/ads_log.php?ref='
  + document.location 
  + '&url=' + window.status;
}
var elements;
elements = document.getElementsByTagName("iframe");
for (var i = 0; i < elements.length; i++)
{
  if (
  (elements[i].src.indexOf('googlesyndication.com') > -1) ||
  (elements[i].src.indexOf('googleadservices.com') > -1) )
  {
    elements[i].onfocus = log;
  }
}