That does sound like a fairly poor implementation. If you had given the same developers ASP.NET to use instead they would have turned out the same poor design though.

There is nothing fundamental in Javascript that makes people code like this. Javascript is actually a very flexible language. It might not be obvious at first, but you can actually build "proper" classes in Javascript (at least as "proper" as you can in things like Visual Basic). There is even a form of implementation inheritance that you can use.

If you want to find out about the classes and OOP-ish features of Javascript, take a look here:

http://mckoss.com/jscript/object.htm
http://www.codeproject.com/aspnet/JsOOP1.asp?df=100&forumid=29873&exp=0&select=686931