// 获取媒体方法（旧方法）
  navigator.getMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMeddia || navigator.msGetUserMedia; 

if (navigator.getMedia) {
    navigator.getMedia({
      video: true
    }, function(stream) {
      mediaStreamTrack = stream.getTracks()[0];

      video.src = (window.URL || window.webkitURL).createObjectURL(stream);
      video.play();
    }, function(err) {
      console.log(err);
    });
  } 

if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
    navigator.mediaDevices.getUserMedia({
      video: true,
      audio: true
    }).then(function(stream) {
      console.log(stream);

      mediaStreamTrack = typeof stream.stop === 'function' ? stream : stream.getTracks()[1];

      video.src = (window.URL || window.webkitURL).createObjectURL(stream);
      video.play();
    }).catch(function(err) {
      console.log(err);
    })
  } 

{
  video: true,
  audio: true
} 

　　<video width="200" height="150"></video>
  <canvas width="200" height="150"></canvas>

  <p>
    <button id="snap">截取图像</button>
    <button id="close">关闭摄像头</button>
    <button id="upload">上传图像</button>
  </p>

  <img id="uploaded" width="200" height="150" /> 

 // 截取图像
  snap.addEventListener('click', function() {
    context.drawImage(video, 0, 0, 200, 150);
  }, false); 

 // 关闭摄像头
  close.addEventListener('click', function() {
    mediaStreamTrack && mediaStreamTrack.stop();
  }, false); 

// 上传截取的图像
  upload.addEventListener('click', function() {
    jQuery.post('/uploadSnap.php', {
      snapData: canvas.toDataURL('image/png')
    }).done(function(rs) {
      rs = JSON.parse(rs);

      console.log(rs);

      uploaded.src = rs.path;
    }).fail(function(err) {
      console.log(err);
    });
  }, false); 

 <?php

  $snapData = $_POST['snapData'];
  $snapData = str_replace('data:image/png;base64,', '', $snapData);
  // $snapData = str_replace(' ', '+', $snapData);

  $img = base64_decode($snapData);

  $uploadDir = 'upload/';
  $fileName = date('YmdHis', time()) . uniqid();

  if (!(file_put_contents($uploadDir . $fileName, $img))) {
    echo json_encode(array('code' => 500, 'msg' => '文件上传失败'));
  } else {
    echo json_encode(array('code' => 200, 'msg' => '文件上传成功', 'path' => $uploadDir . $fileName));
  }

?> 

<script type="text/javascript" src="jquery.js"></script>
  <script type="text/javascript">
  function $(elem) {
    return document.querySelector(elem);
  }

  // 获取媒体方法（旧方法）
  navigator.getMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMeddia || navigator.msGetUserMedia;

  var canvas = $('canvas'),
    context = canvas.getContext('2d'),
    video = $('video'),
    snap = $('#snap'),
    close = $('#close'),
    upload = $('#upload'),
    uploaded = $('#uploaded'),
    mediaStreamTrack;

  // 获取媒体方法（新方法）
  // 使用新方法打开摄像头
  if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
    navigator.mediaDevices.getUserMedia({
      video: true,
      audio: true
    }).then(function(stream) {
      console.log(stream);

      mediaStreamTrack = typeof stream.stop === 'function' ? stream : stream.getTracks()[1];

      video.src = (window.URL || window.webkitURL).createObjectURL(stream);
      video.play();
    }).catch(function(err) {
      console.log(err);
    })
  }
  // 使用旧方法打开摄像头
  else if (navigator.getMedia) {
    navigator.getMedia({
      video: true
    }, function(stream) {
      mediaStreamTrack = stream.getTracks()[0];

      video.src = (window.URL || window.webkitURL).createObjectURL(stream);
      video.play();
    }, function(err) {
      console.log(err);
    });
  }

  // 截取图像
  snap.addEventListener('click', function() {
    context.drawImage(video, 0, 0, 200, 150);
  }, false);

  // 关闭摄像头
  close.addEventListener('click', function() {
    mediaStreamTrack && mediaStreamTrack.stop();
  }, false);

  // 上传截取的图像
  upload.addEventListener('click', function() {
    jQuery.post('/uploadSnap.php', {
      snapData: canvas.toDataURL('image/png')
    }).done(function(rs) {
      rs = JSON.parse(rs);

      console.log(rs);

      uploaded.src = rs.path;
    }).fail(function(err) {
      console.log(err);
    });
  }, false);

  </script>