<div class="g-recaptcha" data-sitekey="key buraya gelecek"></div>
<script>
var response = grecaptcha.getResponse();
if (response.length === 0) {
alert("Hata!! ");
return false;
} else {
// ReCAPTCHA doğrulandı
}
</script>
<script src="https://www.google.com/recaptcha/api.js" async defer></script>