The Web Audio API, developed by the W3C Audio WG
Media Tags Reader (ID3, MP4, FLAC)
Library to simplify the way you create and manipulate sounds with the Web Audio API.
alphaTab is a cross platform music notation and guitar tablature rendering library.
The HTML5 Audio Compatibility Layer
An audio effects library for Web Audio, made by www.dinahmoe.com
Navigable waveform built on Web Audio and Canvas