Many other javascript libraries include their library on their documentation pages, including jQuery, underscore, and d3. This allows for immediate experimentation with the library functions being viewed, using the browser console.
This is a minor consideration, I agree. But it does help people who are just learning the library. It would be a useful feature addition when jstat.github.io is updated.
I would do this myself and issue a pull request, but I'm not sure exactly how.
Thanks for your time.