var $z = jQuery.noConflict();
$z(function(){
var openmenu=null;
$z("div.mega").addClass("open").slideUp(0);  //prepara per il primo passaggio di mouse
$z("#nav>li:has('div.mega')").hoverIntent(
    function(){if(openmenu!=null && openmenu!=this)$z("div.mega",openmenu).slideUp(10);$z("div.mega",this).slideDown("slow");openmenu=this;},
    function(){$z("div.mega",this).slideUp("fast");});
});