使用JS创建用户屏幕截图，并通过ajax问题发送到服务器

<canvas id="screenshotCanvas"></canvas>

navigator.mediaDevices.getDisplayMedia({ video: true })
  .then(function(stream) {
    var videoTrack = stream.getVideoTracks()[0];
    var videoSettings = videoTrack.getSettings();
    var canvas = document.getElementById('screenshotCanvas');
    var context = canvas.getContext('2d');
    canvas.width = videoSettings.width;
    canvas.height = videoSettings.height;
    context.drawImage(videoTrack, 0, 0, canvas.width, canvas.height);
  })
  .catch(function(error) {
    console.error('Error accessing screen media: ' + error);
  });

var canvas = document.getElementById('screenshotCanvas');
var imageData = canvas.toDataURL('image/png');

var xhr = new XMLHttpRequest();
xhr.open('POST', '/upload', true);
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    console.log('Screenshot uploaded successfully');
  }
};
xhr.send('imageData=' + encodeURIComponent(imageData));