Since the "Book" already avoids jQuery in its inline script tags and playpen.js is tiny, I figured I would convert it to plain old JS as well.
Side note: This is a separate issue, but another thing I noticed in my testing is that the "⇱" character doesn't display correctly in Chrome on Windows 7. (Firefox and IE work fine; other browsers not tested)
r? @steveklabnik
Edit: Github didn't like the "script" tag above
Edit 2: Actually, now IE seems to render "⇱" fine for me. Odd.