thinkphp5验证码使用

simple 控制器中

/**
     * 生成验证码
     * @param viod
     */
    public function verify()
    {
        $captcha = new \think\captcha\Captcha();
        $captcha->fontSize = ;
        $captcha->length   = ;
        $captcha->codeSet = '';
        $captcha->useNoise = false;
        return $captcha->entry();
    }

<div class="layui-form-mid">
    <span><img onclick="this.src='{:url("simple/verify")}'" alt="点击更换" title="点击更换" src="{:url('simple/verify')}">
        </span>
</div>