function onProgressChanged(sender, eventArgs) {
    try {
        if (sender != null) {
            var progress = Math.round(eventArgs.progress * 100);
            var pbf = sender.findName("progressBarFill");
            var pt = sender.findName("progressText");
            if (pbf != null)
                pbf.Width = 3 * progress;
            if (pt != null)
                pt.Text = "Nahrávám ... " + progress + "%";
        }
    }
    catch (e) { }
}