chrome浏览器调用摄像头

//var 是定义变量var canvans = document.getElementById("canvas");var video = document.getElementById("video"); //获取video标签var context = canvas.getContext("2d");var con = {audio: false,video: {width: 1920,height: 1080}};//导航 获取用户媒体对象navigator.mediaDevices.getUserMedia(con).then(function (stream) {video.srcObject = stream;video.onloadmetadate = function (e) {video.play();};});function query() {//把流媒体数据画到convas画布上去context.drawImage(video, 0, 0, 400, 300);var imgData = canvans.toDataURL();var imgData_ = imgData.split("base64,")[1];//获取图片//上传服务器$.ajax({type: "post",url: "",data: { "img": imgData_ },success: function (data) {if (result) {alert("登录成功");} else {alert("面容识别失败,请继续验证");}}});}