JSFiddle - React, Tailwind, and code Playground

HTML

<div id="demo" data-user="john">Hello World!</div>

JavaScript

const element = document.getElementById('demo');

// Set a data attribute.
element.dataset.dateOfBirth = '2000-10-10';
// HTML: <div id="demo" data-user="john" data-date-of-birth="2000-10-10">Hello World!</div>

delete element.dataset.dateOfBirth;
// HTML: <div id="demo" data-user="john">Hello World!</div>