check once 1

</body>
</html>
🛠 2. PHP Backend (index.php continued)
Use PHP's mail() (configure SMTP) or PHPMailer to send OTP.

php
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<?php
session_start();

function send_email_otp($email, $otp) {
    $subject = "Your OTP Code";
    $body = "Your OTP is: $otp";
    $headers = "From: no-reply@yourdomain.com\r\n";
    return mail($email, $subject, $body, $headers);
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if (isset($_POST['send_otp'])) {
        $email = $_POST['email'];
        $otp = rand(100000, 999999);
        $_SESSION['email'] = $email;
        $_SESSION['otp'] = $otp;
        $_SESSION['otp_time'] = time();
        if (send_email_otp($email, $otp)) {
            $msg = "OTP sent to $email.";
            echo "<script>document.getElementById('otp-section').style.display='block';</script>";
        } else {
            $msg = "Error sending OTP.";
        }
    }

    if (isset($_POST['verify_otp'])) {
        if (!isset($_SESSION['otp'])) {
            $msg = "Please request OTP first.";
        } else if (time() - $_SESSION['otp_time'] > 300) {
            $msg = "OTP expired. Please request again.";
        } else if ($_SESSION['otp'] == $_POST['otp']) {
            unset($_SESSION['otp']);
            // Serve download
            header('Content-Type: application/octet-stream');
            header('Content-Disposition: attachment; filename="yourfile.pdf"');
            readfile('yourfile.pdf');
            exit;
        } else {
            $msg = "Invalid OTP.";
        }
    }
}
?>