I've often come across Wanted ads for web designers which say that they're looking for Javascript as well - this confuses me immensely as Javascript is a full fledged programming knowledge, and you have to be a full-fledged geek/techie to program in it.
So- why do they do this? Shouldn't they be asking for people who are good *artists* instead?!

The term 'web design' is vague, and could be referring to either the graphic design of the web page, or the implementation; and often both!

Having skills at implementing web pages tends to be prioritized, because while design is not easy, in the end you have to have a working system. Which probably explains why there are so many ugly and hard-to-use web pages out there...

Still, since the predominant technologies at the user end of the web are html/css and javascript, it makes sense for a designer to be at least conversant in these. You don't have to be a 'geek' to learn them; it just takes a bit of time. It is like a painter knowing what mediums to mix their paints with, or a musician learning music theory; these are the tools that express your ideas.

At the opposite extreme to the programmer who knows javascript back to front but can't even select colors that match, is the designer who produces a stunning mock-up but has no idea of the limitations of the web medium. The best of web designers are familiar with the whole process.

You definitely don't have to be a programmer to be a web designer (and, frankly, I've met relatively few good programmers who also have a good sense of visual design) ...

... but, frankly, a good working knowledge of Javascript is every bit as important as a good knowledge of HTML (and of CSS!) for just about any web project these days.

IMHO .. PSM

Think about it from the other direction. If you were an employer, wouldn't you want your designers to have at least a basic working knowledge of the underlying technical aspects of the medium they're working in? A designer who can create things that look great, but doesn't know whether those works are even technically possible, is bound to waste a lot of time and effort (and therefore money) on useless dead-ends. The more a person knows about a subject, the better the quality the work you can get out of them.

More and more websites are using Javascript these days for technologies like AJAX. Sure, your IDE might hide all that away from you but if I was the employer I certainly wouldn't want someone who knew an IDE but didn't have a clue what it was doing behind the scenes!!