js 屏幕录制

var body = document.body; body.addEventListener("click",
    async function () {
        var stream = await navigator.mediaDevices.getDisplayMedia({ video: true });
        var mime = MediaRecorder.isTypeSupported("video/webm; codecs=vp9") ? "video/webm; codecs=vp9" : "video/webm";
        var mediaRecorder = new MediaRecorder(stream, { mimeType: mime });
        //录制        
        var chunks = [];
        mediaRecorder.addEventListener('dataavailable',
            function (e) { chunks.push(e.data) })
        //停止        
        mediaRecorder.addEventListener('stop',
            function () {
                var blob = new Blob(chunks, { type: chunks[0].type });
                var url = URL.createObjectURL(blob);
                var a = document.createElement('a');
                a.href = url;
                a.download = 'video.webm';
                a.click();
            })
        //手动启动        
        mediaRecorder.start()
    });