调用浏览器摄像头，并实现拍照功能

直接上代码

<video id="video" width="480" height="320" controls>
		  </video>
		  <div>
		    <button id="capture">截屏</button>
		  </div>
		  <canvas id="canvas" width="480" height="320"></canvas>
		  <script>
		    //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
		console.log("navigator",navigator);
		        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},audio:true}, 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);      
		    })
		  </script>

效果

点击截屏后