It has a lot to do with the browser. I get next to no stuttering in Chrome, but Firefox it is really evident.
Try exporting your game to a node-webkit.
It has nothing to do with C2 or HTML5 either. You will get the same stuttering with flash games in the same browser.
Go into your graphics card settings and set tripple buffering , and V-sync to on for your browser and see if it helps you.
People who watch NetFlix, and Hulu know all too well about panning images in web browsers.
TL;DR; Web browsers are not a very good platform to make scrolling, or panning animations.