Facebook helps you simplify and enhance user registration and sign in with Facebook account as your login system. In place of own login system best way to authenticate visitors is Sign in with Facebook account. Users no longer need to fill in yet another registration form or remember another username and password to use your site. As long as the user is signed into Facebook, they are automatically signed into your site as well. Sign in with Facebook account login apps are available which can be integrated easily in any web sites. According to a web survey 70% of web users use Facebook account to login to other website or applications. In this post I will describe how to develop “Sign in With Facebook Account” system which can be easily integrated in the PHP/WordPress website. You can fetch basic information and store in the back-end database.
After allow access and authentication Facebook will return below information array-
Array ( [id] => 00000000000000 [name] => Name [first_name] => First Name [last_name] => Last Name [link] => http://www.facebook.com/YourFacebook [username] => UserName [birthday] => 12/01/1982 [bio] => Your Bio on facebook [work] => Array (  => Array ( [employer] => Array ( [id] => 000000000000000 [name] => company name ) ) ) [sports] => Array (  => Array ( [id] => 0000000000000000 [name] => sports name ) ) [gender] => gender [email] => your email id [timezone] => 5.5 [locale] => en_US [languages] => Array (  => Array ( [id] => 106059522759137 [name] => English ) ) [verified] => 1 [updated_time] => 2012-02-07T05:15:58+0000 )
For any questions feel free to comment here. You can also refer this tutorial for details implementation and code.