CDN

<script src="https://cdn.jsdelivr.net/gh/ohno/popup.js@1.0.1/popup.min.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/ohno/popup.js@1.0.1/popup.min.css">

Example 1

<script>popup("Hello World!");</script>

Example 2

<button onClick='popup("Hello World!");'>popup</button>

popup

Example 3

<input id="input" value="TextTextTextTextTextText">
<button onClick='popup(document.getElementById("input").value);'>popup!</button>

popup