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