Custom theme dropdown menu not working

Hi everyone!

I’ve built a custom theme for my blog and I can’t get my dropdown menu working. I followed a tutorial using javascript, but I don’t know javascript very well. I think there is something wrong with this code, but I don’t know how to fix it:

<script type="text/javascript">
(function() {
    $("#navigation ul.menu ul").css({ display: 'none' });
    $("#navigation ul.menu li").hover(function() {
        $(this).find('ul.sub-menu')
            .stop(true, true).delay(10).animate({ "height": "show", "opacity": "show" }, 200 );
    }, function(){
        $(this).find('ul.sub-menu')
            .stop(true, true).delay(10).animate({ "height": "hide", "opacity": "hide" }, 200 );
    });
});
</script>

Any help would be greatly appreciated! I want to be able to make my menus in the wordpress menus function and have the second level navigation actually work!

xxMillie