Alert user if session is going to expire, option to renew session

Question

I have been looking all day for a PHP or JavaScript solution to do this.

I would like to alert the user their session is about to time out (popup), ability to extend the session time.

Here is a visual if you need one on this page

EDIT:

jQuery is the framework if that helps

Answer 1

It's relatively easy:

• Build a JavaScript timer that fires in (session lifetime - 5 min) minutes using setTimeout

• Have the setTimeout function show a confirmation dialog, e.g. using jQuery UI Dialog

• If the user wants to prolong the session, make an Ajax request to an PHP file. If the file uses sessions, this will work to "touch" the session's lifetime

• After making the request, set another setTimeout that will fire when the session is about to expire again.

Answer 2

I would suggest a different approach; just refresh the session for the user anyway. Most unwanted session-deaths happen because of

• a long phonecall
• an unexpected visit
• a meeting

and with a confirmation dialog, the session would already by dead by the time your user comes back - adding only confusion.

Instead:

var refresh_session = function () {
    $.get("/refresh_session.php");
},

fifteen_minutes = 15 * 60 * 1000;

setInterval(refresh_session, fifteen_minutes);

--> happy users! :-)