JSFiddle - React, Tailwind, and code Playground

HTML

<button id="btn">Try it</button>

<div id="test">
</div>

CSS

#test {
    width: 500px;
    height: 500px;
    background-color: lightblue;
}

JavaScript

document.getElementById("test").style.display ="none";

function openTest() {
    document.getElementById("test").style.display = "block";
}

document.getElementById('btn').addEventListener('click', openTest);