JSFiddle - React, Tailwind, and code Playground

by Michel Penke

HTML

<div id="btn-lokal-anmelden" class="btn">

</div>

CSS

.btn {
  width: 100px; 
  height: 100px;
  background: red;
}

.blue {
  background-color: blue;
}

JavaScript

document.getElementById('btn-lokal-anmelden').addEventListener('click', function () {

    document.getElementById('mc_embed_signup')
        .classList
        .toggle('form-fadein');
});