function extmenuShowHide(el) {
  var liNode = document.getElementById('extmenu_li'+el.id.substring(11));
  if (liNode==null) return;
  for(var i = 0; i < liNode.childNodes.length; i++) { 
    if(liNode.childNodes[i].tagName=='UL') {
        var display = liNode.childNodes[i].style.display;
        liNode.childNodes[i].style.display = (display == "block") ? "none" : "block";      
    }
  }
  el.className = el.className == 'ext-menu-expander-open' ? 'ext-menu-expander-close' : 'ext-menu-expander-open';  
}