function enableMenu(id) {
        for (var j = 0; j < menu.length; j++) {
                if (is_object(document.getElementById("submenu" + menu[j]))) document.getElementById("submenu" + menu[j]).style.display = "none";
                if (is_object(document.getElementById("menu" + menu[j]))) document.getElementById("menu" + menu[j]).className = "";
                if (is_object(document.getElementById("spacer" + menu[j]))) document.getElementById("spacer" + menu[j]).style.background = "";
        }

        if (!isNaN(id) && id !== null) {
                if (is_object(document.getElementById("submenu" + id))) document.getElementById("submenu" + id).style.display = "block";
                if (is_object(document.getElementById("menu" + id))) document.getElementById("menu" + id).className = "over";
                if (is_object(document.getElementById("spacer" + id))) document.getElementById("spacer" + id).style.background = "url(/images/mainmenu/nav_over_right.gif) left top no-repeat";
        }
}