Can anyone tell me how to track activity of a users. Using php.

Question

How to track if a user is online or not how much time he is spending on site..

Answer 1

you can use sessions. If session is set for specific user then that person is online. And you can use timestamp for time

Answer 2

And what if the user logged in but not log out..

Answer 3

if user is online then session would be set for specific session variable. if user log out then session would be destroyed. and you can find duration of set session