<dialog> element

index.css

/*bug-in-github-api-content-can-not-be-empty*/

index.html

<dialog id="myDialog">
  <div>this is a dialog</div>
  <button id="close" type="button">close</button>
</dialog>

<button id="show" type="button">show dialog</button>

index.js

const dialogElem = document.querySelector('#myDialog');
const buttonElem = document.querySelector('#show');
const closeElem = document.querySelector('#close');

closeElem.addEventListener('click', (e) => {
  dialogElem.close();
});
buttonElem.addEventListener('click', () => {
  dialogElem.showModal();
});

jsGist.json

{"name":"<dialog> element","settings":{},"filenames":["index.html","index.css","index.js"]}