Detect audio frequency using HTML5 (and more)

If it meets the guidelines, this might make a good "Show HN".

Just look up HTML5 guitar tuner

Demo of pitch detection?

Everything is available already. If you want to see how it works just follow the instructions:

If you want me to see how it works, put up a demo.

It's not my product. I was using it for my project and because I had good experience I decided to share it with others.