i really liked to use fabric.js(<a href="http:&#x2F;&#x2F;fabricjs.com" rel="nofollow">http:&#x2F;&#x2F;fabricjs.com</a>) for a small collaborative drawing tool(<a href="https:&#x2F;&#x2F;github.com&#x2F;wearespindle&#x2F;dotd" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;wearespindle&#x2F;dotd</a>). It runs both on node.js and in the browser, has pretty awesome serialization options and has all batteries included in general.