JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" checked >

JavaScript

$(document).ready(function () {
	$('input')[0].indeterminate = true;
  $('input')[0].addEventListener("click", function (event) {
  	console.log(event.target.checked)
    alert("Check was: " + event.target.checked);
  })
});