JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
  <li></li>
  <li></li>
  <li class="hello">123</li>
  <li class="hello">12</li>
  <li class="hello">1</li>
  <li></li>
</ul>

JavaScript

$( "li.hello" ).first().css( "background-color", "red" );
$( "li.hello" ).last().css( "background-color", "blue" );