window.addEvent('domready', function(){
    $('nav').getChildren().each(function(node){
        if(node.nodeName == 'LI'){
            var children = node.getChildren();
            node.addEvent('mouseenter', function(){
                if(children[1]){
                    children[1].setStyles({
                        'display':  'block',
                        'top':      '15px',
                        'left':     '0px'
                    });
                }
            });
            node.addEvent('mouseleave', function(){
                if(children[1]) children[1].setStyle('display', 'none');
            });
        }
    });
});