In what ways can the interaction between PHP SESSIONs and AJAX functionality be managed to prevent unexpected behavior like retained SESSION content?

When using AJAX functionality in conjunction with PHP SESSIONs, it's important to handle the interaction carefully to prevent unexpected behavior like retained SESSION content. One way to manage this is by ensuring that the AJAX requests include the session ID in the headers, allowing the server to correctly identify and manage the session data. Additionally, you can use session_regenerate_id() to generate a new session ID after certain AJAX requests to prevent session fixation attacks.

// Ensure session ID is included in AJAX requests
$.ajax({
    url: 'example.php',
    type: 'POST',
    beforeSend: function(xhr) {
        xhr.setRequestHeader('X-Session-ID', '<?php echo session_id(); ?>');
    },
    success: function(response) {
        // Handle response
    }
});

// Regenerate session ID after certain AJAX requests
if(/* condition for regenerating session ID */) {
    session_regenerate_id(true);
}