JSFiddle - React, Tailwind, and code Playground

HTML

<button id="replace-all">Replace all</button>
<button id="replace-content">Replace content</button>

CSS

* {
    color: red;
}

JavaScript

document.getElementById("replace-all").addEventListener("click", function(e) {
    e.preventDefault();
    document.write("Everything is gone! Even the styling!");
});

document.getElementById("replace-content").addEventListener("click", function(e) {
    e.preventDefault();
    document.body.innerHTML = "Everything is gone! But not the styling!";
});