typeof NaN === 'number'

I spent most of Sunday picking up the basics of JavaScript.  Overall it went pretty well, I even started writing a little Ajax application.  Syntax is very C-like, but the overall philosophy of the language reminds me a lot of Perl (a million ways to do one thing).  I found the following sites extremely helpful.

Starting JavaScript

The information is a little old on the site, but for picking up the basics it’s fine.  A quick read through and you’ll be well versed enough to start writing some simple things.

JavaScript Toolbox

This one was recommended to me.  I really liked the site, particularly the best practices portion.  As I said, JavaScript seems to have a million ways to do everything, so what’s the best way?  The site goes into detail on common JavaScript gotchas and programming for compatibility and maintainability.  The code samples are also very helpful.

As for ajax, there are some really good tutorials you can find at the bottom of wikipedia’s ajax page.  I’ll have to do some brainstorming in my free time and come up with an app to post.