(function () {
  var menu = document.getElementById('menu');
  var over = false;

  menu['onmouseover'] = function (e) {
    if (over) {
      return;
    }

    menu.className = 'active';
    over = true;
  };

  menu['onmouseout'] = function (e) {
    if (!over) {
      return;
    }

    menu.className = '';
    over = false;
  };
})();