function onSourceDownloadProgressChanged(sender, eventArgs) {
    var myHost = document.getElementById("myPlugin");
    var border = myHost.content.findName("ProgressBorder");
    var fill = myHost.content.findName("ProgressFill");
    var text = myHost.content.findName("ProgressText");
    if(eventArgs.progress)
    {
        fill.Width = eventArgs.progress * border.ActualWidth;
        text.Text = Math.round(eventArgs.progress * 100).toString() + "%";
    }
    else         
    {
        fill.Width = eventArgs.get_progress() * border.ActualWidth; 
        text.Text = Math.round(eventArgs.get_progress() * 100).toString() + "%";
    }
}