How to make a user subscribe to an event in facebook using Graph API?

Question

I would like to users when added to this website event registration also subscribe to the event in the facebook.
The system is already asking for the \"create_event\" ex

Answer 1

It's documented in the event object page:

// RSVP to an Event  
    curl -d "access_token=XXX"  
          https://graph.facebook.com/EVENT_ID/{attending|declined}

So you need to grant the rsvp_event permission.
Example using the php-sdk:

$facebook->api("/EVENT_ID/attending", "post", array("access_token" => "XXXXX"));