var menus = {
  '.actuator' : function (i) {
    i.onclick = function() {
      menu    = document.getElementById('menu_' + i.id.substring(9));
      if (menu) {
        display = menu.style.display;
        menu.style.display = (display == "block") ? "none" : "block";
        return false;
      } else {
        return true;
      }
    }
  }
};

Behaviour.register(menus);