JSFiddle - React, Tailwind, and code Playground

HTML

<div id="bar">
<div id="h2">01</div>
<div id="h2">02</div>
<div id="h2">03</div>
    <div class="h1">1
	<div id="a1">8</div>
    </div>
    <div id="h2">2</div>
</div>

JavaScript

function reverseChild($parent, index)
{
    // Retrieve the child item with the supplied (ZERO BASED!) index
    var childItem = $parent.children('div:nth-child('+ index +')');
    
    // Place it in front of it's immedeate previous sibling.
    childItem.parent().next().after(childItem);
};

$(document).ready(function()
{
	//alert('he');
    reverseChild($('#bar .h1'), 1);
});