JSFiddle - React, Tailwind, and code Playground

by Alexander

CSS

body::after {
  content: "640";
  display: none;
}

JavaScript

console.clear();

// Retreve value from DOM
var cssValue = () =>
	+window.getComputedStyle(
  		document.querySelector('body'),
    	'::after'
    )
  	.content
    .replace(/['"]/g, '');

// Demo only
document.body.innerHTML += '<div>' + cssValue() + '</div>';