Flac.js
FLAC decoder in JavaScript
Wavesurfer.js
Navigable waveform built on Web Audio and Canvas
Flocking
Flocking - Creative audio synthesis for the Web
Waud
Web Audio Library
Timbre.js
JavaScript library for objective sound programming
Buzz
Buzz is a small but powerful Javascript library that allows you to easily take advantage of the new HTML5 audio element. It tries to degrade gracefully on non-modern browsers.
Amplitudejs
A Javascript library that allows you to control the design of your media controls in your webpage -- not the browser. No dependencies (jQuery not required)
Audio5js
The HTML5 Audio Compatibility Layer
Howler.js
Javascript audio library for the modern web.
Web Audio Api
The Web Audio API, developed by the W3C Audio WG
Alpha Tab
alphaTab is a cross platform music notation and guitar tablature rendering library.