<?php
    $name = $_POST['name'];
    $email = $_POST['email'];
    $message = $_POST['message'];
    $from = 'Autor';
    $to = 'moj@mail.pl';
    $subject = 'Wiadomosc ze strony';
    $body = "Od: $name\n E-Mail: $email\n Wiadomosc:\n $message";


if ($_POST['submit']) {
    if (mail ($to, $subject, $body, $from)) {
        print "<script>alert('Wiadomosc wyslana poprawnie');document.location.href='hhttp://www.example.pl/index.html';</script>";
    } else {
        print "<script>alert('Erorr');document.location.href='http://www.example.pl/index.html';</script>";
    }
}
?>

        <form method="post" action="mailer.php">
            <input name="email" placeholder="Adres email" type="email"  required autofocus>
            <input name="name" placeholder="Imię">
            <textarea placeholder="Wpisz tutaj treść wiadomości :)" name="message"></textarea>
            <input id="submit" name="submit" type="submit" value="Wyślij">
        </form>