index.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>reCAPTCHA Test</title>
</head>
<body>
    <h1>Google reCAPTCHA Test</h1>

    <p>
        For available events, check out the <a href="https://github.com/richardszkcs/recaptcha-test">README</a>.
    </p>

    <div class="g-recaptcha"
         data-sitekey="6Ldua2cUAAAAADQagbgv7vhmg5dY88UVk9Paa7CP"
         data-callback="onCaptchaSuccess"
         data-expired-callback="onCaptchaExpired"
         data-error-callback="onCaptchaError"
    ></div>
    <script>
        // fired, when the reCAPTCHA is loaded
        function onCaptchaLoad() {
            console.log('onCaptchaLoad')
        }

        // fired, when the user submits a successful reCAPTCHA response
        function onCaptchaSuccess(token) {
            console.log('onCaptchaSuccess', token)
        }

        // fired, when the reCAPTCHA response expires and the user needs to re-verify
        function onCaptchaExpired() {
            console.log('onCaptchaExpired')
        }

        // fired, when the reCAPTCHA encounters an error
        function onCaptchaError() {
            console.log('onCaptchaError')
        }
    </script>
    <script src="https://www.google.com/recaptcha/api.js?onload=onCaptchaLoad" async defer></script>
</body>
</html>