dedecms自定义表单验证码

<!-- 表单模板 -->
<form action="submit.php" method="post">
    <input type="text" name="captcha" placeholder="请输入验证码" required>
    <img src="captcha.php" alt="验证码">
    <button type="submit">提交</button>
</form>

<?php
session_start();

// 生成随机验证码
$code = substr(md5(uniqid(rand(), true)), 0, 6);

// 将验证码保存到session中
$_SESSION['captcha'] = $code;

// 创建图像
$image = imagecreatetruecolor(100, 30);
$bgColor = imagecolorallocate($image, 255, 255, 255);
$textColor = imagecolorallocate($image, 0, 0, 0);

imagefilledrectangle($image, 0, 0, 100, 30, $bgColor);
imagestring($image, 5, 20, 8, $code, $textColor);

header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>

<?php
session_start();

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $userCaptcha = $_POST['captcha'];
    $sessionCaptcha = $_SESSION['captcha'];

    if ($userCaptcha == $sessionCaptcha) {
        // 验证码正确，处理表单数据
        echo "验证码正确，表单提交成功！";
    } else {
        // 验证码错误，提示用户重新输入
        echo "验证码错误，请重新输入！";
    }
}
?>

<script>
function refreshCaptcha() {
    document.getElementById('captchaImage').src = 'captcha.php?' + new Date().getTime();
}
</script>
<img id="captchaImage" src="captcha.php" alt="验证码" onclick="refreshC悯码()">