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 = 20;
        $captcha->length   = 4;
        $captcha->codeSet = '0123456789';
        $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>