JSFiddle - React, Tailwind, and code Playground

by toddmotto

HTML

<a id="button" href="#">Click a few times, toggle me!</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 + ' ');
}
// toggleClass
function toggleClass(elem, className) {
	var newClass = ' ' + elem.className.replace( /[\t\r\n]/g, " " ) + ' ';
    if (hasClass(elem, className)) {
        while (newClass.indexOf(" " + className + " ") >= 0 ) {
            newClass = newClass.replace( " " + className + " " , " " );
        }
        elem.className = newClass.replace(/^\s+|\s+$/g, '');
    } else {
        elem.className += ' ' + className;
    }
}
document.getElementById('button').onclick = function() {
    toggleClass(this, 'active');
}