What are the best practices for using sessions in PHP to track user progress in interactive content like Flash movies?

To track user progress in interactive content like Flash movies using sessions in PHP, you can store relevant information in session variables such as the current page or level the user is on. This allows you to maintain user progress across different pages or sessions. Make sure to start the session at the beginning of your PHP script and update the session variables as the user progresses through the content.

<?php
// Start the session
session_start();

// Check if user has completed a level and update session variable
if(isset($_GET['completed_level'])){
    $_SESSION['current_level'] = $_GET['completed_level'];
}

// Retrieve user's current level from session
$current_level = isset($_SESSION['current_level']) ? $_SESSION['current_level'] : 1;

// Use $current_level to display appropriate content for the user
echo "User is currently on level: " . $current_level;
?>