google reCAPTCHA

어드민 콘솔 접속 주소

https://www.google.com/recaptcha/admin

HTML 폼작성하기

<!-- recaptcha element -->
<script src="https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit" async defer></script>
<input type="hidden" id="recaptcha_response" name="recaptcha_response" value="" />
<div id="recaptcha_area"></div>

<script type="text/javascript">
var verify_value = "";
var onloadCallback = function() {
	grecaptcha.render('recaptcha_area', {
		'sitekey' : '{어드민 콘솔에서 발급받은 사이트키}',
		'callback' : function(response) {
			if (response != "") {
				verify_value = response;
			}
		},
		'theme' : 'light'
	});
};
</script>
<!-- //recaptcha element -->

<script>
// 폼서브밋시
$("#recaptcha_response").val(verify_value);
</script>

FORM DATA 처리 (php)

<?php
// recaptcha 확인
include_once 'Snoopy.class.php';
$snoopy = new Snoopy;
$data = array(
	"secret" => '어드민 콘솔에서 발급받은 시크릿키',
	"response" => $recaptcha_response
);
$snoopy->submit('https://www.google.com/recaptcha/api/siteverify', $data);
$response = json_decode($snoopy->results);
if (!$response->success) {
	// fail
	exit;
} else {
	// success
}

Snoopy.class.php

https://github.com/endroy/Snoopy