docs: function getLevelDepth(e, id, waypoint, cnt) {
      cnt = cnt || 0;
      if (e.id.indexOf(id) >= 0) {
          return cnt;
      }
      if ($(e).hasClass(waypoint)) {
          ++cnt;
      }
      return e.parentNode && getLevelDepth(e.parentNode, id, waypoint, cnt);
  }