how to implement the functionality: Logout from other devices in php

I want to implement the functionality "Logging out from all devices, but not my device" like Facebook.

Log out everywhere, where else I am logged in

Above link answers the question. But I am new to PHP and I don't get his guide.

To check session_id in Session table with $_SESSION['session_id'], do I need to use Ajax? or Is it a proper way or is there new implementation to achieve the functionality? Please . . .