How can I get a specific parameter from a Facebook page URL?

Question

Well, I'm trying to get a parameter on my Facebook's Page Tab. (This page tab opens an app I've built). So I'm trying to do something like "http://www.facebook.com/mypagename/app_156916377306500?tag=iphone" but nothing happens. Anyone knows how to solve that?

Answer 1

It should be clear from the documentation how to use app_data:

app_data is the ONLY query string parameter in a page tab app's URL which is passed through to your app, it's present in the signed_request which is POSTed to your app's page tab URL, and needs to be decrypted with the app secret (though the SDKs take care of this step for you)

See the Page Tab App documentation and the signed_request documentation for more information