gistfile1.js

// javascript
var takeSnapshot = function (clientId) {
   var videoElem = document.getElementById(clientId);
   var canvas = document.getElementById(“chat-paint-canvas”);
   var ctx = canvas.getContext(‘2d’);
   ctx.drawImage(videoElem, 0, 0, 30, 30);
   return canvas.toDataURL();
};

// html
<canvas height=”30” width=”30” id=”chat-paint-canvas” style=”display: none”></canvas>