You can recall information from Hidden Fields as part of your redirect path, like this:

You can also use them as query strings - for example if you want to add source tracking to your URL:

For security reasons, you cannot use Hidden Fields as the entire URL: 

You cannot use them as the domain part of the URL:

We do not support the use of pure javascript in the redirect field:

Remember that you can edit the text of the Submit button to say anything you like. For more information see this article: Customize system messages.