JSFiddle - React, Tailwind, and code Playground

by Hugo Carneiro

HTML

<div class="title">
  Hello World
</div>

CSS

.title {
  position: relative;
	margin: 25px 20px;
  padding: 0 0 20px;
}

.title::after {
  content: '';
	position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: red;
  height: 4px;
}

JavaScript

var div = document.querySelector(".title");


var str = window.getComputedStyle(div, ':after').backgroundColor = 'blue';
console.log(str)