JSFiddle - React, Tailwind, and code Playground
by oilvier
HTML
<div id="foo1">1</div>
<div id="foo2">2</div>
<div id="foo3">3</div>
JavaScript
console.log(document.getElementById('foo2').nextSibling); // #foo3
console.log(document.getElementById('foo2').previousSibling); // #foo1