JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li>Item 1
<ul class="selecteditem">
<li >Item 1.1</li>
<li>Item 1.2</li>
<li>Item 1.3</li>
</ul>
<ul>
    <li>hello</li>
    <li>manasa</li>
    </ul>
</li>
<li>Item 2</li>
</ul>

JavaScript

$('.selecteditem').after('<li>menu</li>');