How i put myself invisible si my friend can't see me If i am online?

[Bobbie Faulds]

Where you have them as friends on your list, you should be able to uncheck them being able to see when you are online. 

[Bobbie Faulds]

Where you have them as friends on your list, you should be able to uncheck them being able to see when you are online. 

[Lindal Kidd]

Bobbie is right, but it's always possible for a determined person to see if you are on line through other methods.  The only sure way to "hide" from people is to log on with a different account, your "alt".