i get in facebook like all ,but i have some friends that i dont want to be to them ONLINE.Even if i be offline status they can enter by mobile phone and to see that i am on,so there is a code to change this feature? is not permited?
Also, the primary function of FaceBook is for social networking and interactions. Therefore the ability for users to find other users in core to that functionality. If you don't want to be found on FaceBook, do not use FaceBook.