亲测可用：

摄像头拍照

//访问用户媒体设备的兼容方法

function getUserMedia(constraints, success, error) {

if (navigator.mediaDevices.getUserMedia) {

//最新的标准API

navigator.mediaDevices.getUserMedia(constraints).then(success).catch(error);

} else if (navigator.webkitGetUserMedia) {

//webkit核心浏览器

navigator.webkitGetUserMedia(constraints,success, error)

} else if (navigator.mozGetUserMedia) {

//firfox浏览器

navigator.mozGetUserMedia(constraints, success, error);

} else if (navigator.getUserMedia) {

//旧版API

navigator.getUserMedia(constraints, success, error);

}

}

let video = document.getElementById(‘video’);

let canvas = document.getElementById(‘canvas’);

let context = canvas.getContext(‘2d’);

function success(stream) {

//兼容webkit核心浏览器

let CompatibleURL = window.URL || window.webkitURL;

//将视频流设置为video元素的源

console.log(stream);

//video.src = CompatibleURL.createObjectURL(stream);

video.srcObject = stream;

video.play();

}

function error(error) {

console.log(`访问用户媒体设备失败${error.name}, ${error.message}`);

}

if (navigator.mediaDevices.getUserMedia || navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia) {

//调用用户媒体设备, 访问摄像头

getUserMedia({video : {width: 480, height: 320}}, success, error);

} else {

alert(‘不支持访问用户媒体’);

}

document.getElementById(‘capture’).addEventListener(‘click’, function () {

context.drawImage(video, 0, 0, 480, 320);

var imgurl = canvas.toDataURL(‘image/png’);

console.log(imgurl);

})

document.getElementById(‘download’).addEventListener(‘click’, function () {

var dom = document.createElement(“a”);

var imgurl = canvas.toDataURL(‘image/png’);

console.log(imgurl);

dom.href = imgurl;

dom.download = new Date().getTime()+”.png”;

dom.click();

})