I need mobile number of a facebook friend. He is offline. I want to know about him that why he is offline so i need mobile number.
It depends if he has his Mobile number set to Public or Private (private is safer obviously). But if its Public it will be on his Info Page in his Profile.
I clicked on 'Account' -> 'Edit friends' -> 'Contacts' - and there they were: the mobile numbers of 213 friends. I estimated that about fifteen are people I know well, and a good number more are former or current colleagues.
If you want to know the mobile number of any of your fb friend, then firstly you will have to click on the name of that particular friend. This time you can see the profile of your friend. Then click on "info", in this page you will be able to see his/her number. But if your does not share it, you will not be able to see it.
If he is your friend and he shows his number in fb account then you can do that easily by visiting his account.