JSFiddle - React, Tailwind, and code Playground

HTML

<div class="blue">hi!</div>

CSS

div {
    width:100px;
    height:100px;
}

.blue {
     background-color:#00f;   
}

.red {
     background-color:#f00;   
}

JavaScript

$('div.blue').click(function() {
    $(this).toggleClass('red');
});