I have a static website without any server side languages.
Is it possible to pass some custom values whenever a user tries to login then get the data back when the user successfully signed in and comes back to my website from facebook?
I’ve read about signed_request, but that requires PHP.
You’re essentially asking if Facebook will store data for you.
Unfortunately, the answer is no. You need some kind of mechanism on your server that can match a Facebook user to the data you need stored.
You could use local storage, but that’s obviously local to the browser and prone to tampering.