composer安装验证码功能及实例

composer安装命令：composer require topthink/think-captcha

使用验证码：<img src="{:captcha_src()}" id="img" alt="captcha" onclick="reloadImg()">

验证码比对：if(!captcha_check($verifycode)){
   return ['code' => 1 ,'msg' => '验证码不正确'];
}