add google captcha to enable and disable a form button

JS

function recaptchaCallback() {
  document.getElementById("subscribeButton").disabled = false;
}

HTML

<p>
  you will need to replace this with your own sitekey from here: https://www.google.com/recaptcha/
</p>
<div class="g-recaptcha" data-sitekey="6Lfrqf8SAAAAAOdvLdNXgl4_3_RV-gBRrsl4RmhV" data-callback="recaptchaCallback">&nbsp;</div>

<p>
add this to your scripts
</p>
<script src="https://www.google.com/recaptcha/api.js"></script>

<p>
button should look like this
</p>
<input type="submit" value="subscribe" class="footer-email-button" id="subscribeButton" disabled="disabled">

Working Result

Now if you check the google capture it will enable the button

you will need to replace this with your own sitekey from here: https://www.google.com/recaptcha/

add this to your scripts

button should look like this