docs: function () {
          var window = Aria.$window;
          if (typeof(window.orientation) != "undefined") { // check if browser support orientation change
              this.screenOrientation = window.orientation;
              this.isPortrait = this.__isPortrait();
  
              // start listening native event orinetationchange.
              ariaUtilsEvent.addListener(window, "orientationchange", {
                  fn : this._onOrientationChange,
                  scope : this
              });
          }
      }