How do you reduce javascripts cpu use below something like c/c++?

Before you go off on "lock in", note that native apps have a distinct advantage over any web app using javascript. I hate having 20% cpu use for a stupid chat app on a modern i7 system. Most of that "app" is spinning around chasing its own tail making the cpu fetch memory incessantly and blow through cpu cache/tlb. I don't see that happening with native apps nearly as bad.