JSFiddle - React, Tailwind, and code Playground

HTML

<div data-id="9">Hello</div>
<div data-id="9">Hello</div>
<div data-id="9">Hello</div>
<div data-id="10">Hello</div>

CSS

.hi{
color:red;
}

JavaScript

$('div[data-id="9"]').addClass("hi");