I have used JS, TS, ReasonML, CoffeeScript, ASP/C#, PHP, Java, Delphi, C, Rust and probably more which I don't remember to create web applications. I wouldn't say that I used all of them to the same degree and sometimes it was more toying around (like with ReasonML, which is great but lacking tooling), however it is also very interesting to see how they differ and when to use what.