tp5 验证码

<img src="{:captcha_src()}" alt="captcha" onclick="this.src=‘{:captcha_src()}?‘+Math.random()" style="height: 40px; width: 140px"/>

$data=Request::instance()->post();
        //检测验证码是否正确
        $captcha=new Captcha();
        if(!$captcha->check($data[‘code‘])){
            return $this->error("验证码错误",url(‘index‘));
        }