I wonder if some functional languages are used for web development and which are most useful and supported with that goal?
PLT Racket has a web server- it's an up-to-date, actively developed Scheme offshoot, and may be something that you want to look into. Here's some documentation:
http://docs.racket-lang.org/web-server-internal/index.html
There are a few StackOverflow threads that can provide some more answers to this:
state of web development using functional programming language
What are the popular 'web-ready' functional programming languages?