/*
Written by: Adam Crownoble (adam@bryan.edu)
Date: April 3 2006
License: LGPL (http://www.gnu.org/copyleft/lesser.html)
Dependencies: mootools (mootools.net)
*/
var DropDownMenu = new Class({
initialize:function (menuElement) {
	this.menu = menuElement;
	this.id = menuElement.id;
	this.duration = 400;
	this.buttons = [];
	$A(this.menu.getElementsByTagName('li')).each(function (li) {
		if (li.parentNode == menuElement) {
			this.buttons.push($(li));
		}
	}.bind(this));
	this.submenus = $A(this.menu.getElementsByTagName('ul'));
	this.submenus.each(function (submenu) {
		submenu = $(submenu);
		submenu.setStyle('display', 'block');
		submenu.originalHeight = submenu.offsetHeight;
		submenu.effect = new Fx.Style(submenu, 'height', {duration:this.duration, transition:Fx.Transitions.quartOut});
		submenu.effect.set(0);
	}.bind(this));
	this.buttons.each(function (button) {
		button.addEvent('mouseover', this.expand.bindAsEventListener(this));
		button.addEvent('mouseout', this.collapse.bindAsEventListener(this));
	}.bind(this));
}, findButton:function (element) {
	var button = false;
	while (element.parentNode) {
		if (this.buttons.test(element)) {
			button = element;
		}
		element = element.parentNode;
	}
	return button;
}, findSubmenu:function (element) {
	var button = this.findButton(element);
	var submenu = button.getElementsByTagName('ul')[0];
	return submenu;
}, expand:function (event) {
	var submenu = this.findSubmenu(event.target || event.srcElement);
	if (submenu) {
		submenu.effect.clearTimer();
		submenu.effect.start(submenu.originalHeight);
	}
}, collapse:function (event) {
	var submenu = this.findSubmenu(event.target || event.srcElement);
	if (submenu) {
		submenu.effect.clearTimer();
		submenu.effect.start(0);
	}
}});