What is the purpose of the PHPSESSID in the navigation link?

The PHPSESSID in the navigation link is used to maintain session data for a user across multiple pages on a website. It is a unique identifier that allows the server to associate a user with their session data, such as login credentials or shopping cart items. To include the PHPSESSID in the navigation link, you can use the session_id() function to retrieve the current session ID and append it to the URL as a query parameter. This ensures that the user's session data is maintained as they navigate through the website.

<a href="page.php?PHPSESSID=<?php echo session_id(); ?>">Link</a>