SOURCE

//判断浏览器是否支持HTML5 Canvas
window.onload = function () {
try {

//动态创建一个canvas元 ，并获取他2Dcontext。如果出现异常则表示不支持
document.createElement("canvas").getContext("2d");

}
catch (e) {
// document.getElementByIdx("support").innerHTML = "浏览器不支持HTML5 CANVAS";
}
};
//这段代 主要是获取摄像头的视频流并显示在Video 签中
window.addEventListener("DOMContentLoaded", function () {
	var canvas = document.getElementById("canvas");
	context = canvas.getContext("2d");
	video = document.getElementById("video");
	videoObj = { "video": true };
	errBack = function (error) {
		console.log("Video capture error: ", error.code);
	};

	$("#snap").click(function () {
			context.drawImage(video, 0, 0, 330, 250);
		})
		//navigator.getUserMedia这个写法在Opera中好像是navigator.getUserMedianow

	var myGetUserMedia = navigator.getUserMedia ||
			 navigator.webkitGetUserMedia ||
			 navigator.mozGetUserMedia ||
			 navigator.msGetUserMedia;
	//alert("navigator.getUserMedia="+myGetUserMedia);
	if (navigator.getUserMedia){

		navigator.getUserMedia(videoObj, function (stream) {
			video.src = stream;
			video.play();}, errBack);
	}
	else if (navigator.webkitGetUserMedia)
	{
		alert(navigator.webkitGetUserMedia)
		navigator.webkitGetUserMedia(videoObj, function (stream) {
		video.src = window.webkitURL.createObjectURL(stream);
		video.play();
	}, errBack);
	}}, false);

//上传服务器
function CatchCode() {
	var canvans = document.getElementById("canvas");
	//获取浏览器页面的画布对象
	//以下开始编 数据
	var imgData = canvans.toDataURL();
	//将图像转换为base64数据
	var base64Data = imgData.substr(22);
	//在前端截取22位之后的字符串作为图像数据
	//开始异步上
	$.post("uploadImgCode.ashx", { "img": base64Data }, function (data, status) {
		if (status == "success") {
			if (data == "OK") {
					alert("二维 已经解析");
			}
			else {
				// alert(data);
			}
		}
		else {
			alert("数据上 失败");
		}}, "text");
}

xrtxx3<div id="contentHolder">
        <video id="video" style="border:1px solid red;" width="320" height="320" autoplay></video>
        <input type="button" id="snap" style="width:100px;height:35px;" value="Capture" />
        <canvas style="border:1px solid red;" id="canvas" width="320" height="320"></canvas>
    </div>
    日风格yrt一如她999