What potential pitfalls should be considered when trying to pass values from an applet to PHP?

When passing values from an applet to PHP, potential pitfalls to consider include ensuring that the data being passed is properly sanitized to prevent injection attacks, validating the data to ensure it meets expected criteria, and implementing secure communication methods to prevent data interception. It is also important to handle errors gracefully to provide feedback to the user in case of issues.

// Example PHP code snippet for receiving values from an applet

if(isset($_POST['applet_data'])){
    $applet_data = $_POST['applet_data'];

    // Sanitize the data to prevent injection attacks
    $sanitized_data = filter_var($applet_data, FILTER_SANITIZE_STRING);

    // Validate the data to ensure it meets expected criteria
    if(/* validation criteria */){
        // Process the data
    } else {
        // Handle validation error
    }
} else {
    // Handle missing data error
}