JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">

</div>

<button class="X">
click me, now
</button>

JavaScript

// Variante 1: Button per JS erzeugen
// und im div mit ID content einfĂĽgen
const btn = document.createElement("button");
btn.innerText = "click me";
document.getElementById("content").appendChild(btn);

btn.addEventListener("click", e => window.alert("Clicked"));

// Variante 2: Button aus HTML verwenden
const btn2 = document.querySelector("button.X");
btn2.addEventListener("click", e => window.alert("Thank you"))