JSFiddle - React, Tailwind, and code Playground

HTML

<a id="link1">first</a>
<a id="link2">second</a>

JavaScript

function $(id) {
    return document.getElementById(id);
}

function updateFirst() {
    $('link1').innerHTML = $('link2').innerHTML;
}

$('link2').addEventListener('DOMSubtreeModified', updateFirst, false);
setTimeout(function() { $('link2').innerHTML = 'woah'; }, 2000);