code: function (evt) {
              this._move(evt.src);
              this._initialDrag = null;
              this._initialSavedX = null;
              if (this._oldValue[0] !== this.value[0] || this._oldValue[1] !== this.value[1]) {
                  if (this._cfg.onchange) {
                      this._context.evalCallback(this._cfg.onchange);
                  }
              }
          }
docs: Handle the mouse up or touch end during drag end by setting the correct position of the thumb element
  @protected
  @param {aria.DomEvent} evt