code: function( opacity ) {
          if ( this.element[ $.SIGNAL ] && $.Browser.vendor == $.BROWSERS.IE ) {
              $.setElementOpacity( this.element, opacity, true );
          } else {
              $.setElementOpacity( this.wrapper, opacity, true );
          }
      }
docs: Sets the opacity level for the control.
  @function
  @param {Number} opactiy - a value between 1 and 0 inclusively.