dedecms验证码文件

// 示例代码：生成验证码
function generateCaptcha() {
    $captcha = '';
    for ($i = 0; $i < 4; $i++) {
        $captcha .= rand(0, 9);
    }
    $_SESSION['captcha'] = $captcha;
    header('Content-type: image/png');
    $im = imagecreatetruecolor(60, 20);
    $bgColor = imagecolorallocate($im, 255, 255, 255);
    imagefill($im, 0, 0, $bgColor);
    $textColor = imagecolorallocate($im, 0, 0, 0);
    imagestring($im, 5, 10, 3, $captcha, $textColor);
    imagepng($im);
    imagedestroy($im);
}

// 示例代码：验证验证码
function verifyCaptcha($input) {
    if (empty($_SESSION['captcha']) || $input != $_SESSION['captcha']) {
        return false;
    }
    return true;
}

// 示例代码：刷新验证码
function refreshCaptcha() {
    generateCaptcha();
}