function schrijflog()
{
  //if (window.status.indexOf('ga naar') == 0)
  //{
    img = new Image();
    img.src = '/log.php?Ref=' + document.location 
      + '&Url=' + window.status.substring(6) 
      + '&Size=' + event.srcElement.width 
      + 'x' + event.srcElement.height;
 //}
}

var elements;
elements = document.getElementsByTagName("iframe");
for (var i = 0; i < elements.length; i++)
{	
  if(elements[i].src.indexOf('googlesyndication.com') > -1)
  {
    elements[i].attachEvent("onfocus",schrijflog);
	
  }
}