function Toggle(item) {
   obj=document.getElementById(item);
   visible=(obj.style.display!="none")
   key=document.getElementById("x" + item);
   if (visible) {
     obj.style.display="none";
     key.innerHTML="<img src='media/driehoekje.gif' width='11' height='7' hspace='0' vspace='0' border='0'><b>" + item + "</b>";
   } else {
      obj.style.display="block";
      key.innerHTML="<img src='media/driehoekje_neer.gif' width='11' height='7' hspace='0' vspace='0' border='0'><b>" + item + "</b>";
   }
}