Please be careful with the "close to C in speed" claim.

There are only a very small number of languages that can legitimately claim that (C++, Fortran, and sometimes Ada). Java is not one of them. JavaScript is surely not one of them, even with the latest versions of V8.

The only time we see performance remotely close (which still usually means several times slower, at best) to C is for extremely unrealistic micro-benchmarks that have been very heavily optimized to a state where they don't at all resemble real-world code.