Question: Is there a way to get cookies for specific domain (Facebook) and delete all them using JavaScript?

I want to delete cookies for oAuth (Facebook and Gmail) when the user logs out.

Answer: 
No, that is not possible.

You can only access the cookies of your own domain. You can't even see the cookies from a different domain.
So if I understand this correctly you actually want to logout the user from FB... Have you tried using the [FB SDK logout()](http://developers.facebook.com/docs/reference/javascript/FB.logout/) function? That will successfully delete all FB cookies from your domain.

Hope this helps