I've got some AJAX which checks every 5 seconds if there are overdue reminders on my website. The php script which it calls uses the php session and since implementing this users are never logged out after inactivity if they have the site open in their browser, because the session never expires.
I don't want to make the php session expire after a fixed time regardless of activity because I don't want to interrupt any work a user may be in the middle of either.
With that in mind, what could be a solution for this issue?