Save images with progressbar

1

Hello! i have code for save image in server via php:

private function saveIntoServer (event:MouseEvent):void
            {
                
            var temp:BitmapData = new BitmapData(viewer.width,viewer.height);
            temp.draw(viewer);
            
            var jpgEncoder:JPGEncoder = new JPGEncoder(100);
            var jpgStream:ByteArray = jpgEncoder.encode(temp);
 
         var url_req:URLRequest = new URLRequest("save.php");
            url_req.data = jpgStream;
            url_req.method = URLRequestMethod.POST;
 
            var header:URLRequestHeader = new URLRequestHeader ("Content-type", "application/octet-stream");
            url_req.requestHeaders.push(header);
            var u:URLLoader= new URLLoader();
            u.load( url_req );
                              }

and button:

buttonIntoServer.addEventListener(MouseEvent.CLICK, saveIntoSever);

code working good, and in server i have images, but i need add progress bar or output data in textfield progress in % for save status, please, help me

Thanks