Event.observe(window, 'load', SetupIENavigation);

function SetupIENavigation()
{
	var lis = $('Nav').select('li');
	for (var i = 0, li; li = lis[i]; i++)
	{
		if (a = li.select('a')[0])
		{
			a.onmouseover = function(evt)
			{
				if (!evt)
				{
					evt = window.event;
				}
				setHoverStyle(Event.element(evt).parentNode);
			}
		}

		li.onmouseover = function(evt)
		{
			if (!evt)
			{
				evt = window.event;
			}
			setHoverStyle(Event.element(evt));
		}

		li.onmouseout = function(evt)
		{
			if (!evt)
			{
				evt = window.event;
			}
			var src = Event.element(evt);

			if (src.tagName)
			{
				if (src.tagName.toLowerCase() == 'li')
				{
					removeHoverStyle(src);
				}
				else if (src.parentNode.tagName.toLowerCase() == 'li')
				{
					removeHoverStyle(src.parentNode);
				}
			}
		}
	}
}

function setHoverStyle(elem)
{
	var bg_img = elem.currentStyle.backgroundImage;
	if (bg_img.indexOf('_hover') < 0)
	{
		elem.style.backgroundImage = bg_img.replace('.gif', '_hover.gif');
	}
}

function removeHoverStyle(elem)
{
	var bg_img = elem.currentStyle.backgroundImage;
	elem.style.backgroundImage = bg_img.replace('_hover.gif', '.gif');
}