JSFiddle - React, Tailwind, and code Playground

HTML

<button onClick="execCommand('bold', false, null);output.value=input.innerHTML;">Bold</button>
<div style="width: 300px; border: 1px solid #000000;">
<div id="input" contenteditable="true">Some editable text</div>
</div>
<textarea id="output"></textarea>

JavaScript

var output, input;

window.onload = function() {
    output = document.getElementById('output');
    input = document.getElementById('input');
};