Source Code: (back to article)
<body>
<button is="fancy-button">Click me!</button>
<script>
class FancyButton extends HTMLButtonElement {
constructor() {
super();
this.addEventListener('click', () => {
alert('Fancy button clicked!');
});
}
}
customElements.define('fancy-button', FancyButton, { extends: 'button' });
</script>
</body>