function heroUsage(id) {
  pagina = escape(document.location.href);
  ref = escape(document.referrer);
  if((ref == "") || (ref == "undefined")){ ref = "favorieten"; }
  screensize = screen.width + "x" + screen.height;
  screencolor = (navigator.appName.indexOf("Microsoft") > -1) ? screen.colorDepth : screen.pixelDepth;
  document.frames['hero_usage'].location="usage/statistieken_save.php?pagina="+pagina+"&referrer="+ref+"&screensize="+screensize+"&screencolor="+screencolor+"&pages_id="+id+"";
}