There's a functional analysis course at https://www.coursera.org/course/functionalanalysis https://www.coursera.org/course/functionalanalysis. I've only skimmed

There's a functional analysis course at https://www.coursera.org/course/functionalanalysis https://www.coursera.org/course/functionalanalysis. I've only skimmed the notes but they look pretty good, if a bit terse. In general I think the lack of higher mathematics classes is because it would be very hard to evaluate proofs in a MOOC setting.