JSFiddle - React, Tailwind, and code Playground

by David Thomas

HTML

<span id="test">testing</span>

CSS

#test {
    background-color: #5AD9C1;
}

#test.on {
    background-color: #66FF66;
}

JavaScript

function toggleClass(elem, cssClassOn) {
    var test = elem.classList.contains(cssClassOn);
    elem.classList[ test ? 'remove' : 'add' ](cssClassOn);
}

document.getElementById('test').addEventListener('click', function (e) {
    toggleClass(e.target, 'on');
});