`; class Button extends HTMLElement { constructor() { … this.$button .addEventListener('click', () => { console.log(this.message); }); } … } window .customElements .define(‘my-button', Button); my-button.js <script type=“module" src=“./my-button.js”> </script> <div> <h1>hello</h1> <my-button label=“hello” message=“world"> </my-button> </div> hoge.html