$(document).ready(function () {
     
    $('#main_nav li').hover(
        function () {
            //show its submenu
            $('ul.subnav', this).fadeIn("slow") 
								 
        },
        function () {
            //hide its submenu
            $('ul.subnav', this).fadeOut("slow");        
        }
    );
	
	
	 $('#main_nav li ul li').hover(
        function () {
            //show its submenu
            $('ul.subsubnav', this).fadeIn("slow") 
								 
        },
        function () {
            //hide its submenu
            $('ul.subsubnav', this).fadeOut("slow");        
        }
    );
     
});