$$('#navigation_wrapper ul li').each(function(el){

	//mouseover voor menu-items
	el.observe('mouseover', function() {

		if (el.hasClassName('active'))
			return;

		el.className = 'over';
		el.down().className = 'over';
	});

	//mouse-out voor menu-items
	el.observe('mouseout', function() {

		if (el.hasClassName('active'))
			return;

		el.className = '';
		el.down().className = '';
	});

});