JSFiddle - React, Tailwind, and code Playground
HTML
<p class="foo" style="background-color: magenta">text</p>
<hr>
<button id="reset">reset</button>
CSS
.foo {
color: cyan;
}
JavaScript
reset.addEventListener('click', () => {
document.querySelector('.foo').removeAttribute('style')
document.querySelector('.foo').removeAttribute('class')
})