https://www.sammyk.me/best-practice-for-facebook-login-with-the-javascript-sdk-and-php-sdk-v4-1
https://developers.facebook.com/docs/javascript/quickstart
https://developers.facebook.com/docs/facebook-login/access-tokens https://developers.facebook.com/docs/facebook-login/access-tokens#usertokens https://developers.facebook.com/docs/javascript https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow
https://oauth.net/2/ http://stackoverflow.com/questions/13580396/how-to-login-using-facebook-account https://developers.facebook.com/docs/facebook-login/permissions#reference-public_profile https://developers.facebook.com/docs/facebook-login/permissions