how to set session security in php

Description :

Timing-out sessions is a very important action if you are dealing with users logged in to your website or application. If a user logs in to your site in an Internet café and then leaves the computer and café without logging out, how do you stop the next user on that computer from still having access to the previous user’s session? Well you can use the following code:

session_start();

// set time-out period (in seconds)

$inactive = 600;

// check to see if $_SESSION["timeout"] is set

if (isset($_SESSION["timeout"])) {

    // calculate the session's "time to live"

    $sessionTTL = time() - $_SESSION["timeout"];

    if ($sessionTTL > $inactive) {

        session_destroy();

        header("Location: /logout.php");

    }

}

$_SESSION["timeout"] = time();