docs: function DOMWalker_getNode(idSet) {
      var doc = this._controller.window.document;
  
      // QuerySelector seems to be unusuale for id's in this case:
      // https://developer.mozilla.org/En/Code_snippets/QuerySelector
      switch (idSet.getBy) {
        case DOMWalker.GET_BY_ID:
          return doc.getElementById(idSet[idSet.getBy]);
        case DOMWalker.GET_BY_SELECTOR:
          return doc.querySelector(idSet[idSet.getBy]);
        default:
          throw new Error("Not supported getBy-attribute: " + idSet.getBy);
      }
    }