随手记：获取视频第一帧

videoCaptureImage (ideo){
	var scale = 0.3;
	var canvas = document.createElement("canvas"); // 创建一个画布
	canvas.width = video.videoWidth * scale;
	canvas.height = video.videoHeight * scale;
	canvas.getContext('2d').drawImage(video, 0, 0, canvas.width, canvas.height); // getContext:设置画布环境；drawImage:画画
	var imgBase64URL = canvas.toDataURL("image/jpeg"); // 获取图片的url
	console.log(imgBase64URL);
	return imgBase64URL;
};