JSFiddle - React, Tailwind, and code Playground

HTML

<div id="main">
  <div class="sub">
    <div class="a">A</div>
    <div class="b">B</div>
    <div class="c">C</div>
  </div>
  <div class="sub">
    <div class="a">A2</div>
    <div class="b">B2</div>
    <div class="c">C2</div>
  </div>
</div>

JavaScript

function getDiv() {
	var elements = document.getElementById('main').childNodes[1].childNodes[5];
	alert(elements.outerHTML);
  var elements = document.getElementById('main').childNodes[3].childNodes[5];
  alert(elements.outerHTML);
}
getDiv();