$(document).ready(function() {
 var toggle = function(direction, display) {
 return function() {
 var self = this;
 var ul = $("ul", this);
 if( ul.css("display") == display && !self["block" + direction] ) {
 self["block" + direction] = true;
 ul["slide" + direction]("slow", function() {
 self["block" + direction] = false;
 });
 }
 };
 }
 $("li.menu").hover(toggle("Down", "none"), toggle("Up", "block"));
 $("li.menu ul").hide();
});

So far it works fine. I would like to enhance it. If you click on a link 
the submenu should be revealed, 
also if you click on a submenu-item it should stay revealed.
How could i achieve this. Thanks for your help.