PHP表单数据发送：新增向发件人发送回执邮件的需求

先整理下你的环境信息：

• PHP version: 5.3.3
• PHPMailer version: 6.0.5
• CentOS release: 6.9

你当前的表单邮件脚本运行正常，代码如下：

// Only process POST reqeusts.
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Get the form fields and remove whitespace.
    $name = strip_tags(trim($_POST["name"]));
    $phone = trim($_POST["phone"]);
    $email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

    // Check that data was sent to the mailer.
    if ( empty($name) OR empty($phone)) {
        // Set a 400 (bad request) response code and exit.
        http_response_code(400);
        echo "Oops! There was a problem with your submission. Please complete the form and try again.";
        exit;
    }

    // Set the recipient email address.
    $recipient = "email@domain.com";
    // Set the email subject.
    $emailsubject = "New contact from $name";

    // Build the email content.
    $email_content = "Name: $name\n";
    $email_content .= "Email: $email\n\n";
    $email_content .= "Phone:\n$phone\n";

    // Build the email headers.
    $email_headers = "From: $name <$email>";

    // Send the email.
    if (mail($recipient, $emailsubject, $email_content, $email_headers)) {
        // Set a 200 (okay) response code.
        http_response_code(200);
        echo 'Thank You! Your message has been sent.';
    } else {
        // Set a 500 (internal server error) response code.
        http_response_code(500);
        echo "Oops! Something went wrong and we couldn't send your message.";
    }
} else {
    // Not a POST request, set a 403 (forbidden) response code.
    http_response_code(403);
    echo "There was a problem with your submission, please try again.";
}

现在要给提交者的邮箱发送确认邮件，我推荐两种实现方式，考虑到你已经安装了PHPMailer，优先用它会更可靠（比原生mail()函数更稳定，还能降低邮件被标记为垃圾邮件的概率）：

方案一：使用PHPMailer发送两封邮件 #

PHPMailer已经帮你处理了很多邮件发送的细节，比如SMTP配置、编码问题等，修改起来也很方便。下面是完整的修改后的脚本：

// 引入PHPMailer的核心类（请根据你的实际文件路径调整）
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require 'path/to/PHPMailer/src/Exception.php';
require 'path/to/PHPMailer/src/PHPMailer.php';
require 'path/to/PHPMailer/src/SMTP.php';

// Only process POST requests.
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Get the form fields and remove whitespace.
    $name = strip_tags(trim($_POST["name"]));
    $phone = trim($_POST["phone"]);
    $email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

    // 新增对邮箱字段的校验：要给用户发邮件，必须确保这个字段不为空且格式有效
    if (empty($name) OR empty($phone) OR !filter_var($email, FILTER_VALIDATE_EMAIL)) {
        http_response_code(400);
        echo "Oops! There was a problem with your submission. Please complete the form and enter a valid email address.";
        exit;
    }

    try {
        // 初始化PHPMailer实例
        $mail = new PHPMailer(true);

        // 推荐配置SMTP服务器（替换成你自己的邮箱SMTP信息，这能大幅提升邮件到达率）
        // $mail->isSMTP();
        // $mail->Host = 'smtp.yourdomain.com'; // 比如smtp.gmail.com或者你域名的SMTP
        // $mail->SMTPAuth = true;
        // $mail->Username = 'your-email@domain.com';
        // $mail->Password = 'your-email-password';
        // $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
        // $mail->Port = 587;

        // 如果不想用SMTP，也可以继续使用服务器的原生mail()函数
        $mail->isMail();

        // 设置发件人：建议用你自己域名的noreply邮箱，比如noreply@yourdomain.com，避免被拦截
        $mail->setFrom('noreply@yourdomain.com', 'Your Website Name');

        // --------------------------
        // 1. 发送给管理员的邮件（原逻辑）
        // --------------------------
        $adminRecipient = "email@domain.com";
        $adminSubject = "New contact from $name";
        $adminContent = "Name: $name\n";
        $adminContent .= "Email: $email\n\n";
        $adminContent .= "Phone:\n$phone\n";

        $mail->addAddress($adminRecipient);
        $mail->Subject = $adminSubject;
        $mail->Body = $adminContent;
        $mail->send();

        // --------------------------
        // 2. 发送给提交者的确认邮件
        // --------------------------
        // 确认邮件内容，基于你提供的示例扩展
        $userSubject = "Thank you for your submission!";
        $userContent = "Thank you for your submission. These are the details you submitted:\n\n";
        $userContent .= "Name: $name\n";
        $userContent .= "Email: $email\n";
        $userContent .= "Phone: $phone\n\n";
        $userContent .= "We'll review your message and get back to you as soon as possible.";

        // 清空之前的收件人，添加提交者的邮箱
        $mail->clearAddresses();
        $mail->addAddress($email);
        $mail->Subject = $userSubject;
        $mail->Body = $userContent;
        $mail->send();

        // 发送成功后的响应
        http_response_code(200);
        echo 'Thank You! Your message has been sent, and a confirmation email has been sent to your inbox.';
    } catch (Exception $e) {
        // 发送失败的响应，同时输出错误信息方便排查
        http_response_code(500);
        echo "Oops! Something went wrong and we couldn't send your message. Error: {$mail->ErrorInfo}";
    }
} else {
    // Not a POST request, set a 403 (forbidden) response code.
    http_response_code(403);
    echo "There was a problem with your submission, please try again.";
}

方案一的注意点： #

• 务必调整PHPMailer的引入路径，确保和你的项目文件结构匹配
• 强烈建议配置SMTP信息，用自己域名的邮箱发件，这能避免邮件被当成垃圾邮件拦截
• 新增了对邮箱格式的校验，确保提交的邮箱是有效的

方案二：继续使用原生mail()函数发送确认邮件 #

如果你暂时不想切换到PHPMailer，也可以在原脚本的基础上直接添加一段mail()调用，在管理员邮件发送成功后触发：

修改后的核心代码片段（替换原脚本的邮件发送部分）： #

// Send the email.
if (mail($recipient, $emailsubject, $email_content, $email_headers)) {
    // --------------------------
    // 新增：发送确认邮件给提交者
    // --------------------------
    $userSubject = "Thank you for your submission!";
    // 确认邮件内容，基于你提供的示例
    $userContent = "Thank you for your submission. These are the details you submitted:\n\n";
    $userContent .= "Name: $name\n";
    $userContent .= "Email: $email\n";
    $userContent .= "Phone: $phone\n\n";
    $userContent .= "We appreciate your message and will contact you shortly.";

    // 设置确认邮件的头信息，注意不要用用户的邮箱作为发件人，否则容易被拦截
    $userHeaders = "From: Your Website Name <noreply@yourdomain.com>\r\n";
    $userHeaders .= "Reply-To: email@domain.com\r\n"; // 让用户回复时能发到你的工作邮箱

    // 发送确认邮件
    mail($email, $userSubject, $userContent, $userHeaders);

    // Set a 200 (okay) response code.
    http_response_code(200);
    echo 'Thank You! Your message has been sent, and a confirmation email has been sent to your inbox.';
} else {
    // Set a 500 (internal server error) response code.
    http_response_code(500);
    echo "Oops! Something went wrong and we couldn't send your message.";
}

方案二的注意点： #

• 发件人一定要用自己域名的邮箱，不要使用用户的邮箱作为发件人，很多邮件服务商都会拦截这种“伪造发件人”的邮件
• 可以添加Reply-To头，方便用户直接回复到你的工作邮箱

最后，你提到已经知晓PHP 5.3.3的安全隐患，虽然当前脚本可以正常运行，但还是建议尽早升级PHP版本——毕竟PHP 5.3已经停止官方支持多年，存在不少未修复的安全漏洞，升级到更高版本（比如PHP 7.4或以上）会更安全稳定。

内容的提问来源于stack exchange，提问作者TheOrdinaryGeek