var xcol_cur_menu = null;
var xcol_cur_submenu = null;

function show(id, part)
{
    if (!isDOMcompliant()) { return; }
    var menu = document.getElementById("Menu"+part+"_"+id);
    var menus = document.getElementById("NavMenuList");
    if (!menus) return;

    var submenu = menus.getElementsByTagName("ul").item(id);
    if (xcol_cur_submenu == null) {
        submenu.style.visibility = "visible";
    } else {
        xcol_cur_submenu.style.visibility = "hidden";
        submenu.style.visibility = "visible";
    }
    if (xcol_cur_menu == null) {
        menu.className = 'NavMenu'+part+'ButtonOn';
    } else {
        xcol_cur_menu.className = 'NavMenu'+part+'ButtonOff';
        menu.className = 'NavMenu'+part+'ButtonOn';
    }
    xcol_cur_menu = menu;
    xcol_cur_submenu = submenu;
}

function unshow()
{
    if (!isDOMcompliant()) { return; }
    if (xcol_cur_submenu != null) {
        xcol_cur_submenu.style.visibility = "hidden";
    }
    if (xcol_cur_menu != null) {
        xcol_cur_menu.className = 'NavMenu'+part+'ButtonOff';
    }
    xcol_cur_submenu = null;
    xcol_cur_menu = null;
}

function isDOMcompliant()
{
    return document.getElementById && document.getElementsByTagName;
}