How can security measures be implemented in PHP form handling to prevent vulnerabilities such as injection attacks?

To prevent vulnerabilities such as injection attacks in PHP form handling, security measures like input validation, sanitization, and parameterized queries should be implemented. Input validation ensures that data meets certain criteria before processing it, sanitization helps remove potentially harmful characters from input data, and parameterized queries prevent SQL injection attacks by separating SQL code from user input.

// Example code snippet implementing security measures in PHP form handling

// Validate and sanitize user input
$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);
$email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

// Use parameterized queries to prevent SQL injection
$stmt = $pdo->prepare("INSERT INTO users (username, email) VALUES (:username, :email)");
$stmt->bindParam(':username', $username);
$stmt->bindParam(':email', $email);
$stmt->execute();