function hover_top_menu(id) {

    $("#menu_top").delegate("li", "mouseover mouseout", function (e) {
        if (e.type == 'mouseover') {
            if (id != undefined)
                attivatutti();
            jQuery("#menu_top li").not(this).dequeue().animate({ opacity: "0.3" }, 200);
        } else {
            if (id != undefined)
                attivauno(id);
            else
                jQuery("#menu_top li").dequeue().animate({ opacity: "1" }, 200);
        }
    });
}

function attivauno(nome) {
    $(nome).animate({ opacity: "1" }, 200);
    jQuery("#menu_top li").not(nome).dequeue().animate({ opacity: "0.3" }, 200);
    /*$("#menu_top").children("li").each(function () {
        $(this).animate({ opacity: "0.3" }, 200);
    });*/
    //$("#mt1").animate({ opacity: "0.3" }, 200);    
}

function attivatutti() {
    jQuery("#menu_top li").dequeue().animate({ opacity: "1" }, 200);
}