function onSourceDownloadProgressChanged(sender, eventArgs) {    
	var myHost = document.getElementById("Xaml1");    
	var rectBar = myHost.content.findName("rectBar");    
	var rectBorder = myHost.content.findName("rectBorder");    
	if(eventArgs.progress)        
		rectBar.Width = eventArgs.progress * rectBorder.Width;    
	else                 
		rectBar.Width = eventArgs.get_progress() * rectBorder.Width; }