如何錄製使用者的螢幕(')

François Beaufort
François Beaufort

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

<!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>

       
: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;
}
       

       
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.");
});