The difference between the Ajax and Submitting the form is that in Ajax , it is Async call and it does not reload your view. The ajax call receives the response from your action (URL) and does the update with the controls in the view based on your code. Whereas in form submission , the action is called with post data and the view is reloaded again with action response. So you have to check how you update the response message in your view based on these two different behaviours. Hope this helps

Thanks a mill! Got the basic function working using: System.Diagnostics.Debug.Write(System.IO.File.Exists(Path.Combine(path, filename)) ? "File exists." : "File does not exist."); You are a star. I know I should be able to find this info by myself but I am very very early in my development so sometimes it is hard to know what to look for. Thanks!