If you're interested in Hoot, I've started working on an animation library. The idea is to build some useful abstractions over the 2D  Canvas API.  Unfortunately, it's very immature right now,  so I can't recommend it. HOWEVER, it does contain plenty of examples of using Hoot, including:  

Pre-loading images, HTML rendering with SXML, throttling the request animation frame rate, extending the interface between JavaScript and Scheme, Tweening, and Easing. 

So, even if it's not off-the-shelf usable, it contains ideas and code examples that might be helpful. It is based on Spritely's official game template, which, Dave has already posted. Start there! Then if you're looking for more, you are welcome to explore my library
("Protoculture").

Example working in a web browser:  https://bonthron.com/protoculture/

Git repo:  https://git.sr.ht/~bonthron/protoculture