function showNav(){
	if(!$('main-nav')) return;
	$$('#main-nav > ul > li').each(function(li){
		var oldClassName = li.className;
		li.observe('mouseover',function(){			
			var div = this.select('div.sub-nav');
			if(div){
				div[0].style.display = 'block';
				this.addClassName('on')
			}
		}).observe('mouseout',function(){
			var div = this.select('div.sub-nav');
			if(div){
				div[0].style.display = '';
				this.className = oldClassName;
			}
		})
	})
}

document.observe('dom:loaded', function(){
	showNav();
})