(Wordpress) To use social accounts (via janrain) as a main login

I needed to modify a web site that is based on wordpress so that user can only login by social accounts (e.g. Google, Facebook, Twitter, Linkedin, Yahoo etc. The accounts from external sites to the web site itself). It took me awhile but since now it seems working properly, I'm sharing how to do this. Janrain working properly on wordpress is assumed.

Actually it's so simple: modify wp-login.php to remove/comment out text input fields for account ID & password.

As for your reference, I share my version of modified wp-login.php here.

Our kitty sits up!