Record a web mediaElement such as video

record-mediaElement.js

const stream = $0.captureStream();
const recorder = new MediaRecorder(stream);
const allChunks = [];
recorder.ondataavailable = (e) => allChunks.push(e.data);
recorder.start();
// recorder.pause();
// recorder.resume();
recorder.stop();
var fullBlob = new Blob(allChunks);

var link = document.createElement('a');
link.style.display = 'none';
var downloadUrl = window.URL.createObjectURL(fullBlob);
link.href = downloadUrl;
link.download = 'name-of-your-video.webm';
document.body.appendChild(link);
link.click();
link.remove();