如何錄製使用者的螢幕(')

François Beaufort
François Beaufort
GitHub

只要使用 Screen Capture API，網頁版平台即可分享分頁、視窗和螢幕畫面。getDisplayMedia() 方法可讓使用者選取要擷取做為媒體串流的畫面。接著，你可以使用 MediaRecorder API 錄製這個串流，或透過網路與他人分享。您可以透過 showOpenFilePicker() 方法，將錄製內容儲存至本機檔案。

以下範例將展示如何以 WebM 格式錄製使用者的螢幕畫面、在同一個頁面上在本機預覽，以及將錄製內容儲存到使用者的檔案系統。

let stream;
let recorder;

shareScreenButton.addEventListener("click", async () => {
  // Prompt the user to share their screen.
  stream = await navigator.mediaDevices.getDisplayMedia();
  recorder = new MediaRecorder(stream);
  // Preview the screen locally.
  video.srcObject = stream;
});

stopShareScreenButton.addEventListener("click", () => {
  // Stop the stream.
  stream.getTracks().forEach(track => track.stop());
  video.srcObject = null;
});

startRecordButton.addEventListener("click", async () => {
  // For the sake of more legible code, this sample only uses the
  // `showSaveFilePicker()` method. In production, you need to
  // cater for browsers that don't support this method, as
  // outlined in https://web.dev/patterns/files/save-a-file/.

  // Prompt the user to choose where to save the recording file.
  const suggestedName = "screen-recording.webm";
  const handle = await window.showSaveFilePicker({ suggestedName });
  const writable = await handle.createWritable();

  // Start recording.
  recorder.start();
  recorder.addEventListener("dataavailable", async (event) => {
    // Write chunks to the file.
    await writable.write(event.data);
    if (recorder.state === "inactive") {
      // Close the file when the recording stops.
      await writable.close();
    }
  });
});

stopRecordButton.addEventListener("click", () => {
  // Stop the recording.
  recorder.stop();
});

瀏覽器支援

MediaDevices.getDisplayMedia()

瀏覽器支援

  • 72
  • 79
  • 66
  • 13

資料來源

MediaRecorder API

瀏覽器支援

  • 47
  • 79
  • 25
  • 14.1

資料來源

File System Access API 的 showSaveFilePicker()

瀏覽器支援

  • 86
  • 86
  • x
  • x

資料來源

其他資訊

操作示範

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link
      rel="icon"
      href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🖥️</text></svg>"
    />
    <title>How to record the user's screen</title>
  </head>
  <body>
    <h1>How to record the user's screen</h1>
    <button id="startShareScreenButton">Start sharing screen</button>
    <button id="stopShareScreenButton" disabled>Stop sharing screen</button>
    <button id="startRecordButton" disabled>Start recording</button>
    <button id="stopRecordButton" disabled>Stop recording</button>
    <video autoplay muted playsinline></video>
    <pre id="logs"></pre>
  </body>
</html>

CSS


        :root {
  color-scheme: dark light;
}
html {
  box-sizing: border-box;
}
*,
*:before,
*:after {
  box-sizing: inherit;
}
body {
  margin: 1rem;
  font-family: system-ui, sans-serif;
}
button {
  display: block;
  margin-bottom: 4px;
}
video {
  display: block;
  margin-top: 10px;
  max-width: 100%;
  background: black;
  max-height: 480px;
}
pre {
  color: red;
  white-space: pre-line;
}

JS


        const video = document.querySelector('video');
const startShareScreenButton = document.querySelector('#startShareScreenButton');
const stopShareScreenButton = document.querySelector('#stopShareScreenButton');
const startRecordButton = document.querySelector('#startRecordButton');
const stopRecordButton = document.querySelector('#stopRecordButton');

let stream;
let recorder;

startShareScreenButton.addEventListener("click", async () => {
  // Prompt the user to share their screen.
  stream = await navigator.mediaDevices.getDisplayMedia();
  recorder = new MediaRecorder(stream);
  // Preview the screen locally.
  video.srcObject = stream;

  startRecordButton.disabled = false;
  stopShareScreenButton.disabled = false;
  log("Your screen is being shared.");
});

stopShareScreenButton.addEventListener("click", () => {
  // Stop the stream.
  stream.getTracks().forEach(track => track.stop());
  video.srcObject = null;

  stopShareScreenButton.disabled = true;
  startRecordButton.disabled = true;
  stopRecordButton.disabled = true;
  log("Your screen is not shared anymore.");
});

startRecordButton.addEventListener("click", async () => {
  // For the sake of more legible code, this sample only uses the
  // `showSaveFilePicker()` method. In production, you need to
  // cater for browsers that don't support this method, as
  // outlined in https://web.dev/patterns/files/save-a-file/.

  // Prompt the user to choose where to save the recording file.
  const suggestedName = "screen-recording.webm";
  const handle = await window.showSaveFilePicker({ suggestedName });
  const writable = await handle.createWritable();

  // Start recording.
  recorder.start();
  recorder.addEventListener("dataavailable", async (event) => {
    // Write chunks to the file.
    await writable.write(event.data);
    if (recorder.state === "inactive") {
      // Close the file when the recording stops.
      await writable.close();
    }
  });

  stopRecordButton.disabled = false;
  log("Your screen is being recorded locally.");
});

stopRecordButton.addEventListener("click", () => {
  // Stop the recording.
  recorder.stop();

  stopRecordButton.disabled = true;
  log("Your screen has been successfully recorded locally.");
});