I must admit that I’ve avoided learning javascript for several years, mostly because I always thought it was a hacky means of fiddling with the DOM of rendered pages on the fly (woo hoo!), and more recently because AJAX and JSON scare the hell out of me from a security point of view.

I’ll be interested in what else you have to say about it as you get deeper into the language, and maybe change my mind over whether it is worth spending the time for me to learn it…

Cheers,
Gary

The power of JavaScript has certainly become more evident over the years, especially if you take into account how sophisticated webmail services have become (e.g. zimbra).
Sad to say though, as you mentioned AJAX and JSON are more or less security nightmares, although i suspect that is mainly because developers aren’t security minded in general when dealing with javascript requests (e.g. exec’ing JSON instead of parsing it). There are also still too many unknown’s with regards to security in the actual browser (e.g. bookmarklets are inherently insecure).

I think its worth learning JavaScript if you are also thinking about developing Flash-based apps (e.g. using FLEX), as the scripting language that uses (i.e. ActionScript) is more or less based on ECMAScript, otherwise known as JavaScript.