Oauth 2.0 - Redirect URL takes user to the canvas page on my website and not to the iframe on Facebook

I开发者_如何学C have looked around and around for hours now and messed about with different pieces of code and I am at a loss.

I am only a begginner at PHP so I am learning it as I go along. I get how authorisation works and I have managed to get the app authorised, just once the app has been authorised the application redirects the user to the full canvas page on my website instead of displaying my canvas page in the iframe within Facebook.

I can't for the life of me work out how to change this so the redirect redirects to the iframe and not my website.

I would really appreciate some help on this matter.

(P.s. I know there are similar topics to this and I have read quite a few and have found nothing that has helped me solve my problem)

Many Thanks Scott