HTML5 audio has matured significantly since it was introduced in 2009. In its early days, for example, none of the major browsers supported the same audio file types, of which there are many. Today, however, they all support MP3, making it easy to render basic audio in a browser.
A more elaborate tutorial is available on GitHub, where you can contribute to the discussion.
UPDATE (29 April 2015): This project is now responsive. Try it on a phone: http://roy.vanegas.org/html5-audio