code: function getAllKeys () {
          if (!privateSerializer) {
              privateSerializer = new ariaUtilsJsonJsonSerializer(true);
          }
  
          var storedMap = storage.getAttribute("kMap");
          return storedMap ? privateSerializer.parse(storedMap) : {};
      }
docs: IE throws an error when you try to set an attribute with invalid characters such as an empty space, $ % and
  others, or even if it starts with a number. For this reason we generate a new safe key and keep a map of the
  association between the original key and the generated one. This map is stored in user data as well, in order to
  be reused when you close and reopen the tab. <br />
  <br />
  Get all the keys in the map
  @return {Object} a map of user key - generated key