Is there any proper Certification for Javascript, that covers all the advanced topics of Javascript including the DOM (Document Object Model), BOM (Browser Object Model) and CSS Object Model, that can really evaluate the skills?
I've no idea how to scale myself on my JS skills, so any suggestions would be beneficial.
W3Schools states:
The JavaScript exam will be taken over the Internet, at any time and from any location, but the exam should be supervised by a person selected by the exam candidate.
I'd count that as a yes. Costs some money, though.
What for though? As something to put on a CV, I'd say whatever you find would be worthless. If you, as a programmer who cares about his craft, has to go searching to find it, you can be damned sure that any future employer won't have heard of it either. Being able to point to a single functioning website which you built would be far more valuable for you.
If you're looking for a test just for your own benefit, to see how you rate, that's another story... I just wouldn't pay any money for it. Answer some questions on Stack Overflow, and you'll quickly find out how you rate in the eyes of your peers :p
I don't think there's any reliable one. There are some online, but most seem to be testing very basic questions.
JavaScript is getting more and more important. Advanced understanding of it (like OOP, memory usage, frameworks) is needed, but no good certificates are around. JavaScript will have more access to hardware (Geolocation, camera, audio) just like Flash and other technologies, but it remains non-proprietary.
As an alternative, I would a) do answering a lot in forums like Stackoverflow, b) publish an web app that uses advanced technology and c) write reviews on JavaScript books. Nothing is more direct than getting a certificate, but these are all we could do now.
I agree with TK: have a Web presence where you can showcase your skills, and write reviews of relevant books and other resources. Writing in this way gives you a chance to demonstrate literacy, critical thinking, and that you've made an effort to keep abreast by seeking out and listening to a variety of experts.