Ah, but then you have to have a JVM, so "having Rhino" is a challenge. But I guess if you're not on a UNIX system where Perl, Python and Ruby are pervasive and always available (or a couple of clicks or commands away), then having Java around is just the same amount of effort. It also lacks "beginner" tutorials that are focused on the kind of interaction that you need to understand to build applications. JavaScript is a weird interactive model, because you are talking to the DOM to do anything interesting, which is a mess--it's really way more complex than beginners usually grasp (I have a hard time with it, and I've been developing in several languages since I was a kid).

That said, I think in the end JavaScript is going to be the world's most popular language for almost everything, including web applications. I happen to agree with Yegge in that regard. But it's still somewhat less friendly to learners than the other languages I mentioned.

Anyway, if Rhino (or some other standalone JavaScript engine) becomes popular I'd reckon that in a year there will be some good tutorials for interactive JavaScript, and it'll become a great choice for learning programming. I happen to think JavaScript is a very pretty language. A few confusing quirks (Function vs. function vs. = {}(); modules, for example), but overall it offers some great functionality in a pretty simple syntax and low keyword manner.