使用AJAX检查PHP会话是否存在或过期

Question

1. How to set the php session time out, I'm trying like below, but I dont think it works

   ini_set("session.gc_maxlifetime", 600);

2. How to find out whether a php session exists or expired using ajax (javascript)?

Regards

Answer 1

For #1 use session_set_cookie_params(). To expire after 600 seconds

session_set_cookie_params(600)

(note unlike the regular setcookie function the session_set_cookie_params uses seconds you want it to live, it should not be time() + 600 which is a common mistake)

For number 2 just make a small script called through AJAX:

<?php
session_start()

if( empty($_SESSION['active']) ) {
     print "Expired"
}
else {
     print "Active"
}

?>

On the Javascript side (using JQuery)

$.get('path/to/session_check.php', function(data) {
     if( data == "Expired" ) {
         alert("Session expired");
     } else if (data == "Active" ) {
         alert("Session active");
     }
 });