$(document).ready(function () {
    $('#nav li').hover(
        function () {
            //show its submenu
            //$('ul', this).slideDown(300);
        	$(this).children("ul").slideDown(300);
       
        },
        function () {
            //hide its submenu
            //$('ul', this).slideUp(300);    
            $(this).children("ul").slideUp(500);  
        
        }
    );
     
});