If you ask me, no chance to rule the web. JavaScript has been the standard for a very long time now. Because JS is not a flawless language dozens of js precompilers have been created till now, so the competition is pretty rough. Swift tries to be functional and provides you a way to use immutable data structures, but it is neither functional nor opinionated enough to force immutablity. With that said I personally don't think that it brings something new to the already existing web ecosystem. It sure is a nicer alternative to obj-c though.