I think Google is actually thinking javascript is going to be the base machine language of the browser. They seem to be investing a lot of effort on the V8 engine. http://code.google.com/p/v8/
Does V8 compile to a bytecode similar to Java? I know that it does JIT compilation to native code and then caches it for future use. If it happens to have a bytecode representation, we could read the Google tealeaves and conclude that Google sees compiled JavaScript as an ugly steppingstone toward a binary representation of client-side code.
AFAIK, not any remotely standardized bytecode, no. Of course, there are some data structures in between the strings of characters and the native code, but I don't think there's any talk of guaranteeing anything that would warrant calling them "byte code".