Javascript shares a problem with C++: it is hard to find non-crap documentation and tutorials that won't lead new coders subtly (or not so subtly) into bad habits that are hard to break later. With C++ or Javascript, the first few google results for any newbie question are likely to be pretty bad.

If you have access to a really good Javascript programmer who uses modern techniques and libraries (use of jQuery, prototype, coffescript and/or node.js are all good signs), and can get them to supply you with help or at least review the help you're gtting from others, then that's cool. If not, then stay away from JS until you're a good programmer and you have a direct practical need for it.