var selectedNavItem = null;

(function ($) {
	$(document).ready(function() {
		$("#navigation li").mouseenter(
			function () {
				if (selectedNavItem !== null)
					$("#sub" + selectedNavItem.attr('id')).removeClass('subnav-on');
					
				$("#sub" + $(this).attr('id')).addClass('subnav-on');
				selectedNavItem = $(this);
			}
		);
	});
} (jQuery));