window.addEvent('domready', function() {
    $('dropdown').getElements('li.menu').each(function(elem) {
        var list = elem.getElement('ul.links');
        var myFx = new Fx.Slide(list).hide();
        elem.addEvents({
            'mouseenter': function() {
                myFx.cancel();
                myFx.slideIn();
            },
            'mouseleave': function() {
                myFx.cancel();
                myFx.slideOut();
            }
        });
    })
});