+ // first add with no value
+ this.add( 'targetWindow', null );
+ // This avoids SecurityErrors when setting a window object in x-origin iframe'd scenarios.
+ this.targetWindow.set = function( to ) {
+ var from = this._value;
+
+ to = this._setter.apply( this, arguments );
+ to = this.validate( to );
+
+ if ( null === to || from === to ) {
+ return this;
+ }
+
+ this._value = to;
+ this._dirty = true;
+
+ this.callbacks.fireWith( this, [ to, from ] );
+
+ return this;
+ };
+ // now set it
+ this.targetWindow( params.targetWindow || defaultTarget );
+
+