JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box" class=""></div>
<div id="box2"></div>

CSS

#box, #box2 { width: 100px; height: 100px; border: 1px solid #000; }
.red { background: red; }

JavaScript

$('#box, #box2')
    .click(function() {
        $(this).toggleClass('red', 1000);
});