Snippet for quick contact form handling with vanilla PHP/JS + $.ajax

form-handler.php

<?php

$subject = 'Temat wiadomości';
$recipient = 'recipient@example.com';

$output = [
    'success' => 'Dziękujemy za wiadomość.',
    'error' => 'Coś poszło nie tak. Spróbuj ponownie.',
];

$data = [
    'name' => $_POST['name'],
    'company' => $_POST['company'],
    'email' => $_POST['email'],
    'message' => $_POST['message'],
    'honeypot' => $_POST['honeypot'],
];

if ($data['honeypot'] === 'true') {
    echo json_encode([
        'success' => 'true',
        'message' => $output['error'],
    ]);

    return;
}

$messageBody = "
<strong>Imię i nazwisko:</strong> ${data['name']}<br/>
<strong>Firma:</strong> ${data['company']}<br/>
<strong>E-mail:</strong> ${data['email']}<br/>
<strong>Wiadomość:</strong> ${data['message']}<br/>
";

$headers = 'From: sender@example.com' . "\r\n" .
    'Reply-To: ' . $data['email'] . "\r\n" .
    'X-Mailer: PHP/' . phpversion() . "\r\n" .
    'Content-Type: text/html; charset=utf-8';

$mail = mail($recipient, $subject, $messageBody, $headers);

echo json_encode([
    'success' => 'true',
    'message' => $mail ? $output['success'] : $output['error'],
]);

form.js

$('.js-contact-form').on('submit', (e) => {
  e.preventDefault();

  const form = e.target;
  const button = form.querySelector('button');
  const notification = form.querySelector('.form-output');
  const data = {
    name: form.fullname.value,
    company: form.company.value,
    email: form.email.value,
    message: form.message.value,
    honeypot: form.rules.checked,
  };

  $.ajax({
    url: `/form-handler.php`,
    method: 'POST',
    dataType: 'json',
    data,
    beforeSend() {
      button.textContent = 'Wysyłanie...';
      notification.textContent = '';
    },
    success(response) {
      button.textContent = 'Wyślij';
      notification.textContent = response.message;
      form.reset();
    },
  });
});