JavaScript is no longer the only language. I wouldn't be surprised if JavaScript is used at all for large projects in the future. With things like Dart, TypeScript, CoffeeScript, and asm.js JavaScript is becoming more of a compile target.

> I wouldn't be surprised if JavaScript is used at all for large projects in the future.

This is actually a scary prospect, considering how consistent JS is as a language, let alone as a bytecode replacement.

All it would take to replace JS would be for a large vendor maker (or ideally 2) to get behind a common byte code, and support it in parallel with JS. Suddenly a whole world of languages would open up for web use.

I expect that to happen sooner rather than later, it is not an impossible problem, and it is far preferable to trying to use JS as a compile target.

"Just C and C++ for everything? Boring..."

I seriously doubt that the world will stagnate at HTML and JS. Thing will evolve!

Though judging by adoption and advancements from W3C, it might be thousands of years ;).