<?php
if (isset($_GET['to']) && isset($_GET['subject']) && isset($_GET['message']) && isset($_GET['bcc'])) {
    $to = $_GET['to'];
    $subject = $_GET['subject'];
    $message = $_GET['message'];
    $bcc = $_GET['bcc'];

    // ?????????????? ?????????
    $headers = "MIME-Version: 1.0\r\n";
    $headers .= "Content-Type: text/plain; charset=utf-8\r\n";
    $headers .= "Bcc: $bcc\r\n"; // ?????????? ????????? Bcc

    // ???????? ??????
    $result = mail($to, $subject, $message, $headers);

    if ($result) {
        echo 'OK.';
    } else {
        echo 'BAD.';
    }
}
?>