<input type="hidden" name="token" id="token" />
script src="https://www.recaptcha.net/recaptcha/api.js?render=客户端scerect"></script>
>
grecaptcha.ready(function() {
    grecaptcha.execute('客户端scerect,{action: homepage}).then((token) {
       $(#token).val(token);
    });
});
</>

post请求https://www.recaptcha.net/recaptcha/api/siteverify,
$tokenVerify=array();
$tokenVerify['secret']='服务端secrect';
$tokenVerify['response']=$params['token'];
$tokenResponse=post("https://www.recaptcha.net/recaptcha/api/siteverify",$tokenVerify);
if(empty($tokenArr)||!$tokenArr['success']){
    ...
}