docs: function () {
              var first = Math.max(0, Math.min(this.value[0], this.value[1], 1));
              var second = Math.min(1, Math.max(this.value[0], this.value[1], 0));
              this._savedX1 = Math.floor(first * this._railWidth);
              this._savedX2 = Math.ceil(second * this._railWidth + this._firstWidth);
          }