JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<body>
<h2> The heading </h2>
<p>The paragraph.</p>
<div style="border:1px solid; margin-bottom:10px;">
 <span>This is a span element</span>
  <p>The first paragraph in div.</p>
  <p>The second paragraph in div</p>
  <p>The last paragraph in div.</p>
</div>
<div style="border:1px solid; margin-bottom:10px;">
  <p>The first paragraph in div.</p>
  <p>The second paragraph in div.</p>
  <p>The last paragraph in div.</p>
</div>
<div style="border:1px solid; margin-bottom:10px;">
  <p>The first paragraph in div.</p>
</div>
</body>

JavaScript

$(document).ready(function(){
 $("p:first-child").css("background-color", "yellow");
});