How to use Resemble.js ? Can it be used to compare one just canvas drawing and one image?

Question

I have two image object ak whiteimg. User is clearing the area of one image and i want to compare the two images every 2 sec.

<script src="http://huddle.github.io/Resemble.js/resemble.js"></script>


var timer=setInterval(function(){
resemble(ak).compareTo(whiteimg).onComplete(function(){
console.log(data);
},2000);

Am i doing anything wrong ? I am also waiting for images to load and then performing operation.

Error in Console: Uncaught SyntaxError: Unexpected end of input (index:1)