Building a FB PAGE

Okay so i get everything about building a page. Only one thing kinda boggles me right now. Can you not insert a viral script to the main page anymore. If so, could anyone kindly tell me how to do it. Also do viral like scripts even work anymore? Like the actual "invite friends to unlock page"?

They only prompt people to invite their friends.
I don't know if there is anyway to allow access to the page once friend request have been sent.
You might be able to do it with an app but you will need to know PHP or another coding lang.