Highlight menu on hover with delay and display submenu

// attach events to all menu items
function addHooks() 
  {
  var menuLinks = document.getElementById('head_nav1').getElementsByTagName('a');
 
  for(var i = 0; i < menuLinks.length; i++) 
    {
    addEvent(menuLinks[i], "mouseover", activateMenuWithDelay);
    addEvent(menuLinks[i], "mouseout", deactivateMenu);
    }
  }
 
// helper for addHooks(), needed for different browser behaviour
function addEvent (elm, type, fnc) 
  {
	if (window.addEventListener) 
	  {
		elm.addEventListener(type, fnc, false);
	  }
	// IE
	else 
	  {
		elm.attachEvent("on" + type, fnc);
	  }
  }
 
function activateMenuWithDelay()
  {
  var oThis = this;
  var ident;
 
  // IE & Opera
  if (window.event) 
    { 
    srcElm = window.event.srcElement;
    ident = srcElm.attributes["ident"].value;
    oThis = srcElm;
    } 
  // W3C DOM (FF, Mozilla, Safari)
  else 
    { 
    ident = this.attributes["ident"].value;
    }
 
  if(oThis.timer)
    {
    clearTimeout(oThis.timer);            
    }
  oThis.timer = setTimeout(function() { displaySubMenu.apply(oThis, [ident,oThis]); }, 130);
  }
 
function deactivateMenu()
{
  var oThis = this;
 
  // IE & Opera
  if (window.event) 
  { 
    oThis = window.event.srcElement;
  } 
 
  if(oThis.timer)
  {
    clearTimeout(oThis.timer);
  }
}