No, the idea is that you could compile whatever language you like into byte code that would then run in the browser.
Javascript might still be the main language on the web (and would probably continue to be handled in the same way it is now) but you could also use other languages.
Sure, so it'd be hard to come up with a bytecode standard that worked really well for anything you might want to run on it - but you could probably come up with a reasonable bytecode / VM that would work reasonably well for most things.
For example, imagine that there was no threat of being sued by Oracle, etc. You could just use the JVM - that already has lots of things that compile to it which work reasonably well. I'm not arguing that we should use the JVM, but only that something like the JVM seems to work reasonably well.
Anyway - having a way that's OK or reasonable to run (say) Ruby in the browser is a lot better than the current situation where there is no such way (without using proprietary stuff).
Javascript might still be the main language on the web (and would probably continue to be handled in the same way it is now) but you could also use other languages.