JSFiddle - React, Tailwind, and code Playground

HTML

<div id ="example">Lorem ipsum dolor sit amet, consectetur adipisicing elit.</div>

JavaScript

var example = document.getElementById('example'),
    rng = document.createRange(),
    newNode = document.createTextNode('lalala ');

rng.setStart(example.firstChild, 6);
rng.setEnd(example.firstChild, 12);
rng.deleteContents();
rng.insertNode(newNode);