问php邮件程序如何设置自动响应

EN

    <?php
    // Message Vars
    $msg = '';
    $msgClass = '';

    // Check For Submit
    if(filter_has_var(INPUT_POST, 'submit')){
        // Get Form Data
        $name = htmlspecialchars($_POST['name']);
        $email = htmlspecialchars($_POST['email']);
        $message = htmlspecialchars($_POST['message']);

        // Check Required Fields
        if(!empty($email) && !empty($name) && !empty($message)){
            // Passed
            // Check Email
            if(filter_var($email, FILTER_VALIDATE_EMAIL) === false){
                // Failed
                $msg = 'Please use a valid email';
                $msgClass = 'alert-danger';
            } else {
                // Passed
                $toEmail = '';
                $subject = 'Contact Request From '.$name;
                $body = '<h2>Contact Request</h2>
                    <h4>Name</h4><p>'.$name.'</p>
                    <h4>Email</h4><p>'.$email.'</p>
                    <h4>Message</h4><p>'.$message.'</p>
                ';

                // Email Headers
                $headers = "MIME-Version: 1.0" ."\r\n";
                $headers .="Content-Type:text/html;charset=UTF-8" . "\r\n";

                // Additional Headers
                $headers .= "From: " .$name. "<".$email.">". "\r\n";

                if(mail($toEmail, $subject, $body, $headers)){
                    // Email Sent
                    $msg = 'Your email has been sent';
                    $msgClass = 'alert-success';
                } else {
                    // Failed
                    $msg = 'Your email was not sent';
                    $msgClass = 'alert-danger';
                }
            }
        } else {
            // Failed
            $msg = 'Please fill in all fields';
            $msgClass = 'alert-danger';
        }
    }
?>

    <div class="container"> 

      <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
          <div class="form-group">
              <label>Name</label>
              <input type="text" name="name" class="form-control" value="<?php echo isset($_POST['name']) ? $name : ''; ?>">
          </div>
          <div class="form-group">
            <label>Email</label>
            <input type="text" name="email" class="form-control" value="<?php echo isset($_POST['email']) ? $email : ''; ?>">
          </div>
          <div class="form-group">
            <label>Message</label>
            <textarea name="message" class="form-control"><?php echo isset($_POST['message']) ? $message : ''; ?></textarea>
          </div>
          <br>
          <button type="submit" name="submit" class="btn btn-primary">Submit</button>
      </form>
    </div>