JS Canvas Snap Shot Webcam Coverd Checker W\ SUPER FLIR SRC

<style>
  body{
filter:brightness(334%);
    filter:invert(334%)
  }
</style>
<center>
<body bgcolor="black" oncclick="setInterval(snapshot,33);">
<video id="video" width="640" height="640" autoplay></video>
<button id="snapshot" class="Button" onclick="canvas.">Snapshot Image</button>
<canvas id="canvas" width="640" height="640"></canvas>
<script>
window.addEventListener("DOMContentLoaded", function() {
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var video = document.getElementById('video');
var mediaConfig =  { video: true,audio:false};
var errBack = function(e) {
console.log('An error has occurred!', e)
};
if(navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
navigator.mediaDevices.getUserMedia(mediaConfig).then(function(stream) {
  video.src = window.URL.createObjectURL(stream);
video.play();


});
}
else if(navigator.getUserMedia) {
navigator.getUserMedia(mediaConfig, function(stream) {
video.src = stream;
video.play();
  video.src = window.URL.createObjectURL(stream);
video.play();
    ctt=getBase64Image(video);

}, errBack);
}
  var cct;
  var ctt
  document.getElementById('snapshot').addEventListener('mouseup', function() {
 cct=getBase64Image(video)
  ctt=getBase64Image(video);

context.drawImage(video, 0, 0, 640, 640);
ctt=getBase64Image(video);
if(ctt<501991){
document.body.innerHTML=document.body.innerText=("<font color='red'>Cam Is Hidden!!")
}
             else{
               document.body.innerHTML=document.body.innerText=("<font color='green'>Cam Is Not Hidden!!")
             }
});
}, false);
function getBase64Image(img) {
var canvas = document.createElement("canvas");
    canvas.width = img.width;
    canvas.height = img.height;
    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0);
    var dataURL = canvas.toDataURL("image/png");
    return dataURL.length-4000;
}

</script>