video Uncaught (in promise) DOMException 报错

调用video.play()报错Uncaught (in promise) DOMException

解决办法 video.play()放于video.onloadedmetadata内部

//video.play();     报错   
video.onloadedmetadata = function () {
            video.play();
            console.log('打开摄像头');
        };