How can the session data be effectively cleared in PHP to ensure that it is not retained when navigating back in a frameset?

When navigating back in a frameset, the session data may still be retained, leading to potential security risks or data leakage. To effectively clear the session data in PHP, you can use the session_unset() function to remove all session variables. Additionally, you can use session_destroy() to destroy the session completely. This ensures that any sensitive data stored in the session is properly cleared.

// Clear session data
session_unset();
session_destroy();