How to make a universal facebook app for all sites?

Question

Facebook

Hi all.
I need to make a Facebook login application, for example, so that people can leave comments on the site while logging in from other social networks. But Facebook blocks if a person tries to log in from a site that is different from the site that I wrote in the Facebook settings. What if you make a universal application that will be used by 10 sites?

Answer 1

10 and register
or wait until Facebook allows anyone to steal data (at least 100 years old)