JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
  <li> hi </li>
  <li> hoi </li>
  <li> privyet </li>
  <li class="selected"> bonjour </li>
  <li> hallo </li>
    </ul>

JavaScript

var items = $("ul li");
var index = items.index(items.filter(".selected"));
$(document.body).append("<hr><p>Selected index: " + index + "</p>");