Event.observe(window, 'load', function() {
	var menu = new DropDownMenu($('navigation'));
});

var DropDownMenu = Class.create();

DropDownMenu.prototype = {
	initialize: function(menuElement) {
		menuElement.childElements().each(function(node){
			// if there is a submenu
			var submenu = $A(node.getElementsByTagName("ul")).first();
			if(submenu != null){
				// make sub-menu invisible
				Element.extend(submenu).setStyle({display: 'none'});
				// toggle the visibility of the submenu
				node.onmouseover = node.onmouseout = function(){
					Element.toggle(submenu);
				}
			}
		});
	}
};