;
mediaRecorder.ondataavailable = (event) => if (event.data.size > 0) recordedChunks.push(event.data); ;
mediaRecorder.onstop = () => const blob = new Blob(recordedChunks, type: 'video/webm' ); const url = URL.createObjectURL(blob); recordedVideo.src = url; downloadLink.href = url; downloadLink.download = 'screen-recording.webm'; downloadLink.style.display = 'inline'; ;
The days of relying on third-party software for screen recording are fading. With the Screen Capture API (often searched as api grabador de pantalla ), modern web browsers can capture screen content, individual windows, or browser tabs directly using JavaScript. api grabador de pantalla
const constraints = video: displaySurface: "window" // "browser", "window", or "monitor" ; Instead of recording locally, you can add the MediaStream to an RTCPeerConnection :
startBtn.onclick = async () => try // Request screen capture mediaStream = await navigator.mediaDevices.getDisplayMedia( video: true, audio: true // Captures microphone + system audio (where supported) );
// Show preview previewVideo.srcObject = mediaStream; ; mediaRecorder
While it has limitations (especially with system audio), it eliminates the need for browser extensions or native plugins for most basic to intermediate screen capture needs.
function stopRecording() if (mediaRecorder && mediaRecorder.state !== 'inactive') mediaRecorder.stop(); mediaStream.getTracks().forEach(track => track.stop()); previewVideo.srcObject = null; startBtn.disabled = false; stopBtn.disabled = true;
: Copy the code above into an .html file, open it locally or via HTTPS, and click “Start Capture”. You’ll have a working screen recorder in minutes. Have you built something with the Screen Capture API? Share your experience in the comments below. function stopRecording() if (mediaRecorder && mediaRecorder
mediaRecorder.start(1000); // Capture data every second startBtn.disabled = true; stopBtn.disabled = false;
// Stop recording if user clicks the browser's native "Stop sharing" button mediaStream.getVideoTracks()[0].onended = () => stopRecording(); ; catch (err) console.error("Error: " + err);
const peerConnection = new RTCPeerConnection(); mediaStream.getTracks().forEach(track => peerConnection.addTrack(track, mediaStream); ); // Then send via SDP offer/answer You can overlay drawings or text on the preview <video> using a <canvas> element layered on top. Limitations and Browser Support | Feature / Browser | Chrome | Firefox | Safari | Edge | |------------------|--------|---------|--------|------| | getDisplayMedia() | ✅ | ✅ | ✅ (13+) | ✅ | | System audio capture | ✅ (flag) | ❌ | ❌ | ✅ | | Cursor capture | ✅ | ✅ | ✅ | ✅ | | Recording quality control | Via MediaRecorder | Same | Limited | Same |