function tree2(menu_class,menu_id) {
 var div=document.getElementById(menu_id);
 if (div.style.display == "block") div.style.display="none";
 else {
  var sib=div.parentNode.childNodes;
  for (var i=0; i < sib.length; i++)
   if (sib[i].className == menu_class) sib[i].style.display="none";
  div.style.display="block";
 }
}