JSFiddle - React, Tailwind, and code Playground

by Nick Hulea

HTML

<a id="button" href="#">Add a new class!</a>
<a id="button" href="#">Add a new class!</a>

CSS

a {
    margin:20px;
    padding:10px 15px;
    background:#FFD202;
    border-radius:5px;
    color:#222;
    display:inline-block;
    text-decoration:none;
}
.active {
    background:#000;
    color:#FFD202;
}

JavaScript

// hasClass
function hasClass(elem, className) {
	return new RegExp(' ' + className + ' ').test(' ' + elem.className + ' ');
}
// addClass
function addClass(elem, className) {
    if (!hasClass(elem, className)) {
    	elem.className += ' ' + className;
    }
}
document.getElementById('button').onclick = function() {
    addClass(this, 'active');
    this.innerHTML = 'Woo! Nice work.';
}