PHP Form Handling

Process and validate form submissions.

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A form sends data to a PHP script with method="post". The script reads it from $_POST.

Validation checklist

Check that required fields are not empty.
Validate formats with filter_var($email, FILTER_VALIDATE_EMAIL).
Clean input with trim().
Escape output with htmlspecialchars() to prevent XSS.
Protect forms with a CSRF token (frameworks like Laravel do this for you).

Key Takeaways: PHP Form Handling

Mastering PHP Form Handling helps you write clean and reliable PHP code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.

PHP Form Handling Code Example

PHP

<?php
$errors = [];
$email = "";

if ($_SERVER["REQUEST_METHOD"] === "POST") {
    $email = trim($_POST["email"] ?? "");
    if ($email === "") {
        $errors[] = "Email is required";
    } elseif (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $errors[] = "Invalid email format";
    }
}
?>
<form method="post">
  <input name="email" value="<?= htmlspecialchars($email) ?>">
  <button>Subscribe</button>
</form>
<?php foreach ($errors as $error): ?>
  <p style="color:red"><?= $error ?></p>
<?php endforeach; ?>

Output

(after submitting "abc")
Invalid email format

Run this example on your own computer. The "Get Started" lesson shows how to set it up.

PHP Form Handling Practice Exercises

Check what you learned in “PHP Form Handling”.

/ 2 solved

Fill in the blank

Escape output to prevent XSS.

echo ($name);

✓ Correct! Not quite. Try again.

Multiple choice

Which function checks that an email address is valid?

filter_var($email, FILTER_VALIDATE_EMAIL) is_email($email) check_email($email) email_valid($email)

✓ Correct! Not quite. Try again.

to save your exercise progress.

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PHP Include & Require

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PHP Form Handling

Validation checklist

💡 Key Takeaways: PHP Form Handling

PHP Form Handling Code Example

PHP Form Handling Practice Exercises

Key Takeaways: PHP Form Handling