Event.observe(window,'load',menus);
function menus(){
	var todos_li = $A($('menu').getElementsByTagName('li'));
	todos_li.each(function(li){
			Event.observe(li,'mouseover',aparece_menu.bindAsEventListener(li));
			Event.observe(li,'mouseout',desaparece_menu.bindAsEventListener(li));
		});
}
function aparece_menu(){
	var actual = this.getElementsBySelector('ul');
	if(actual.size()>0){
		this.addClassName('active');
		actual[0].style.display = 'block';		
	}
}
function desaparece_menu(){
	var actual = this.getElementsBySelector('ul');
	if(actual.size()>0){
		this.removeClassName('active');
		actual[0].style.display = 'none';
	}
}