Supported as in “you can install an interpreter on most machines”: yes

But for JS it’s already there. You can just write a program, upload it someone, send someone a link and it runs. And it’s even sandboxed.

(Although thanks to webassembly, that will be true for many more languages as well, so maybe my argument is void)

Not saying it should be used for everything, but it is a pretty decent language nowadays (lots of the annoying parts have been fixed in the last 15yrs). Although the main benefit imho is, that it is the closest thing we have to an interpreted language that runs everywhere.