Screen Capture API：getDisplayMedia 屏幕采集与录制

概述`navigator.mediaDevices.getDisplayMedia` 允许采集屏幕、窗口或标签页视频流。在安全上下文下提示用户选择来源，可与 `MediaRecorder` 结合录制输出。用法/示例const stream = await navigator.mediaDevices.getDisplayMedia({ video: { frameRate: 30 } }) const rec = new MediaRecorder(stream, { mimeType: 'video/webm;codecs=vp8', videoBitsPerSecond: 4000000 }) const chunks = [] rec.ondataavailable = e => chunks.push(e.data) rec.start() setTimeout(() => { rec.stop() }, 5000) rec.onstop = () => { const blob = new Blob(chunks, { type: 'video/webm' }) const url = URL.createObjectURL(blob) } 工程建议设置合适的帧率与码率，兼顾清晰度与能效；在低端设备降低规格。注意权限提示与用户选择；采集音频需显式开启并遵守平台政策。处理捕获源变化与停止事件，确保录制流程稳健并释放资源。参考与验证MDN：getDisplayMedia — https://developer.mozilla.org/docs/Web/API/MediaDevices/getDisplayMediaMDN：MediaRecorder — https://developer.mozilla.org/docs/Web/API/MediaRecorderweb.dev：Screen Capture — https://web.dev/articles/screen-capture