How can PHP beginners avoid common pitfalls when handling user input in registration forms?

One common pitfall when handling user input in registration forms is failing to properly sanitize and validate the data before using it in database queries or other operations. To avoid this, beginners should always sanitize user input to prevent SQL injection attacks, validate input to ensure it meets expected criteria, and use prepared statements when interacting with databases. 

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

// Validate input
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "Invalid email address";
    exit;
}

// Use prepared statements for database queries
$stmt = $pdo->prepare("INSERT INTO users (username, email) VALUES (:username, :email)");
$stmt->bindParam(':username', $username);
$stmt->bindParam(':email', $email);
$stmt->execute();

Keywords

SQL injection XSS attacks input validation htmlspecialchars prepared statements

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