$(document).ready(function() {

	$("ul#topnav li").hover(function() { //Hover over event on list item
		$(this).css({ 'background' : 'url(menu/images/bk_menu_on.jpg)'}); //Add background color and image on hovered list item
		$(this).find("span").show(); //Show the subnav
	} , function() { //on hover out...
		$(this).css({ 'background' : 'url(menu/images/bk_menu_off.jpg)'}); //Ditch the background
		$(this).find("span").hide(); //Hide the subnav
	});

});