docs: function (cb) {
              var hcC = this._hashChangeCallbacks;
              if (hcC != null) {
                  var len = hcC.length, i = 0;
                  while (i < len && hcC[i] != cb) {
                      i++;
                  }
                  if (i < len) {
                      hcC.splice(i, 1);
                      if (hcC.length === 0) {
                          this._hashChangeCallbacks = null;
                          this._removeHashChangeInternalCallback();
                      }
                  }
              }
          }