var prev_menu = ''; 
  var sel_menu = '';
  var sel_submenu = '';

  function menu(menuitem) {
    if (document.getElementById(menuitem)) {
      close_menu();
      prev_menu = '';
      var selected_menuitem = document.getElementById(menuitem).style;
      if (selected_menuitem.display == "block") {
        selected_menuitem.display = "none";
      } 
      else {
        selected_menuitem.display = "block";
        if (document.getElementById('news')) {
          var nieuws = document.getElementById('news').style;
          nieuws.display = "none";
        }
      }
      prev_menu = document.getElementById(menuitem).id;
    } 
  }

  function close_menu() {
    if (document.getElementById('news')) {
      var nieuws = document.getElementById('news').style;
      nieuws.display = "block";
    }
    if (sel_submenu) {
      document.getElementById(sel_submenu).className = 'menu_sub_item';
    }
    sel_submenu = '';

    if (document.getElementById(prev_menu)) {
      document.getElementById(prev_menu).style.display = "none";
    }

  }

  function menu_click(menuitem) {
    if ((document.getElementById(sel_menu)) && (sel_menu != menuitem.id)) {
      document.getElementById(sel_menu).className = 'menu_main_item';
    }
    if (menuitem != document.getElementById(sel_menu)) {
      menuitem.className = 'menu_selected_main_item';
      sel_menu = menuitem.id;
    }
  }

  function menu_click_sub(menuitem) {
    if ((document.getElementById(sel_submenu)) && (sel_submenu != menuitem.id)) {
      document.getElementById(sel_submenu).className = 'menu_sub_item';;
    }
    sel_submenu = menuitem.id;

  }

  function menu_over(menu_object, menu_class) {
    if (menu_object.id != sel_menu) {
      menu_object.className = menu_class;
    }
  }

  function menu_over_sub(menu_object, menu_class) {
    if (menu_object.id != sel_submenu) {
      menu_object.className = menu_class;
    }
  }