JSFiddle - React, Tailwind, and code Playground
HTML
<div class="message">
<span>Menu 1</span><span>Menu 2</span>
</div>
JavaScript
$('.message span:last-child').after('<span>Menu 3</span>');
<div class="message">
<span>Menu 1</span><span>Menu 2</span>
</div>
$('.message span:last-child').after('<span>Menu 3</span>');