Need help with script

[joeafusco]

So, I found this script on a tutorial for working with javascript. I'm extremely new, and I don't know how to make the adjustment that I'm looking for.

The script is for a menu, when you click one of the top menu items, it drops down a couple more. My issue, is that when I click one of the main items, I must click it again to make it go away. I was hoping that once I clicked off the menu, or into another menu item, it would 'hide' the other menu selections.

Here is the script:

var toggleMenu = {
	init : function(sContainerClass, sHiddenClass) {
		if (!document.getElementById || !document.createTextNode) {return;} // Check for DOM support
		var arrMenus = this.getElementsByClassName(document, 'ul', sContainerClass);
		var arrSubMenus, oSubMenu, oLink;
		for (var i = 0; i < arrMenus.length; i++) {
			arrSubMenus = arrMenus[i].getElementsByTagName('ul');
			for (var j = 0; j < arrSubMenus.length; j++) {
				oSubMenu = arrSubMenus[j];
				oLink = oSubMenu.parentNode.getElementsByTagName('a')[0];
				oLink.onclick = function(){toggleMenu.toggle(this.parentNode.getElementsByTagName('ul')[0], sHiddenClass); return false;}
				this.toggle(oSubMenu, sHiddenClass);
			}
		}
	},
	toggle : function(el, sHiddenClass) {
		var oRegExp = new RegExp("(^|\\s)" + sHiddenClass + "(\\s|$)");
		el.className = (oRegExp.test(el.className)) ? el.className.replace(oRegExp, '') : el.className + ' ' + sHiddenClass; // Add or remove the class name that hides the element
	},
/* addEvent function from [URL unfurl="true"]http://www.quirksmode.org/blog/archives/2005/10/_and_the_winner_1.html[/URL] */
	addEvent : function(obj, type, fn) {
		if (obj.addEventListener)
			obj.addEventListener(type, fn, false);
		else if (obj.attachEvent) {
			obj["e"+type+fn] = fn;
			obj[type+fn] = function() {obj["e"+type+fn](window.event);}
			obj.attachEvent("on"+type, obj[type+fn]);
		}
	},
/*
Written by Jonathan Snook, [URL unfurl="true"]http://www.snook.ca/jonathan[/URL]
Add-ons by Robert Nyman, [URL unfurl="true"]http://www.robertnyman.com[/URL]
*/
	getElementsByClassName : function(oElm, strTagName, strClassName){
	    var arrElements = (strTagName == "*" && document.all)? document.all : oElm.getElementsByTagName(strTagName);
	    var arrReturnElements = new Array();
	    strClassName = strClassName.replace(/\-/g, "\\-");
	    var oRegExp = new RegExp("(^|\\s)" + strClassName + "(\\s|$)");
	    var oElement;
	    for(var i=0; i<arrElements.length; i++){
	        oElement = arrElements[i];      
	        if(oRegExp.test(oElement.className)){
	            arrReturnElements.push(oElement);
	        }   
	    }
	    return (arrReturnElements)
	}
};
toggleMenu.addEvent(window, 'load', function(){toggleMenu.init('menu','hidden');});

Any help would be appreciated.