Audiolet
A JavaScript library for real-time audio synthesis and composition from within the browser
Wad
Web Audio DAW. Use the HTML5 Web Audio API for dynamic sound synthesis. It's like jQuery for your ears.
Sound Manager 2
A JavaScript Sound API supporting MP3, MPEG4 and HTML5 audio + (experimental) RTMP, providing reliable cross-browser/platform audio control in as little as 10 KB. BSD licensed.
Alpha Tab
alphaTab is a cross platform music notation and guitar tablature rendering library.
Tone.js
A Web Audio framework for making interactive music in the browser.
Audio.js
A cross-browser javascript wrapper for the html5 audio tag
Web Audio Api
The Web Audio API, developed by the W3C Audio WG
Mp3.js
A JavaScript MP3 decoder for Aurora.js
Flac.js
FLAC decoder in JavaScript
Audio5js
The HTML5 Audio Compatibility Layer
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)