Superglobals & Handling Form Data

PHP automatically populates several superglobal arrays with incoming request data — available in any scope, with no global keyword needed.

// From an HTML form: <form method="POST"><input name="email"></form>
$email = $_POST['email'] ?? '';

// From a URL like page.php?id=5
$id = $_GET['id'] ?? null;

echo $_SERVER['REQUEST_METHOD']; // "GET" or "POST"

Common mistakes

• Reading $_POST['email'] directly without the ?? '' fallback — if the field is missing, this raises a warning instead of failing gracefully.
• Trusting $_POST/$_GET values without validating them first — they're raw user input, covered fully in Level 3's Security Fundamentals.