If you would like to save the url of the site that the user came from, you can use this code. This will only work if you also go to the Formidable -> global settings page and turn on user tracking.

Use this code to change the redirect URL when an entry is being updated.

If you are using a User ID field, this function is not needed. Use this function if you are collecting email addresses from users who are not logged in, and would like to show an avatar using only the email address.
[25 avatar=40]
25 = the field ID
40 = the size of the avatar