<script>
// Wait to run this code until the document has loaded.
document.addEventListener('DOMContentLoaded', function() {
    // Find the element with the hash that you set on the button. There should be
    // just one since you used a unique hash. Change #setThisToYourHash to the
    // unique hash you chose for your button.
    var button = document.querySelectorAll("a[href='#setThisToYourHash']")[0];
    button.className += " " + "crankwheel-com-showu-launch-button";
});
</script>