Make the Mailchimp Subscriber popup appear on click

clickable-element.html

<!-- This is the HTML element that, when clicked, will cause the popup to appear. -->

<button id="open-popup">Subscribe to our mailing list</button>

mailchimp_popup.js

<script type="text/javascript" src="//s3.amazonaws.com/downloads.mailchimp.com/js/signup-forms/popup/embed.js" data-dojo-config="usePlainJson: true, isDebug: false"></script>
<script>
(function MailChimpPopup(r) {
  var loader;
  r(["mojo/signup-forms/Loader"], function(l) {
    loader = l;
  });
  function openPopup(e) {
    e.preventDefault();
    document.cookie = "MCEvilPopupClosed=; expires=Thu, 01 Jan 1970 00:00:00 UTC";
	loader.start({"baseUrl":"mc.us11.list-manage.com","uuid":"YOUR_UUID_GOES_HERE","lid":"YOUR_LID_GOES_HERE"})
  }
  var openBtn = document.getElementById('open-popup');
  if (openBtn) {
    openBtn.addEventListener('click', openPopup);
  }
}(require));
</script>

This fork loads the external script mojo/signup-forms/Loader immediately after page load to speed up the popup once the button is clicked.