JSFiddle - React, Tailwind, and code Playground
by al3x88
HTML
<div>
<div id="1">1</div>
<div id="2">2</div>
<!-- commento -->
<div id="3">3</div>
</div>
JavaScript
console.log(document.getElementById('2').previousSibling);
console.log(document.getElementById('3').previousSibling);
console.log(document.getElementById('2').previousElementSibling);
console.log(document.getElementById('3').previousElementSibling);