JSFiddle - React, Tailwind, and code Playground
HTML
<ul id="myList">
<li>Item 1</li>
<li><span>Item 2</span></li>
<li>Item 3</li>
<li>Item 4</li>
</ul>
JavaScript
var parentNode = document.getElementById('myList');
alert('count: ' + parentNode.childElementCount);
alert('length: ' + parentNode.children.length);