JSFiddle - React, Tailwind, and code Playground
HTML
<button class="btn">btn</button>
<button class="btn active">btn active</button>
<div class="card active">card inactive</div>
JavaScript
console.log(document.querySelectorAll('.btn'))
console.log(document.querySelectorAll('.btn.active'))
console.log(document.querySelectorAll('.btn, .active'))