What are the advantages and disadvantages of using PHP sessions for passing and storing data in a web application?

Using PHP sessions for passing and storing data in a web application is a common practice due to its simplicity and ease of use. The advantages of using PHP sessions include the ability to store data securely on the server side, maintain user state across multiple pages, and easily access the data throughout the user's session. However, some disadvantages of using PHP sessions include potential security vulnerabilities if not implemented properly, increased server load due to storing session data on the server, and limitations on the amount of data that can be stored in a session.

// Start a PHP session
session_start();

// Store data in the session
$_SESSION['username'] = 'john_doe';

// Retrieve data from the session
$username = $_SESSION['username'];

// Destroy the session
session_destroy();