I need the proper code that will figure out you are "logged" onto GOOGLE PLUS or YELP or FACEBOOK.
The logic is below-
When a user clicks on a link (that is directed to my website) -- the website should determine whether that user is already "logged" into google plus (or gmail), OR [url removed, login to view] or FACEBOOK. Many users are already logged via their browsers into Google (gmail), Facebook or yelp.com. We want to know whether they are logged in or not.
If it is logged in to any of them, then it should return a value (that is logged in or not).
** The code cannot prompt the user any more links or re-directions to determine whether it's logged in or not.
I just need the specific code and it must work for all three.
If the code doesn't work - then payment is not made.
To verify that you read the instructions, please tell me what is the capital of Argentina - otherwise all responses will be ignored.