There are mx:HTTPService tag<mx:HTTPService id="ntreeXML" resultFormat="text"useProxy="false" result="fHTTPServiceResult(event)"fault="fHTTPServiceFault2(event)"/>and<mx:Tree id="mainTree" change="changeEvt(event)" ......../> public function changeEvt(event:Event):void { .......... ntreeXML.url = "h...