Wave.js : Audio visualizer library for javascript. Create dynamic animations that react to an audio file or audio stream.
SoundManager 2 : Using HTML5 and Flash, SoundManager 2 provides reliable cross-platform audio under a single JavaScript API.
Band.js : An interface for the Web Audio API that supports rhythms, multiple instruments, repeating sections, and complex time signatures.
jsfx : This is a javascript library (with frontend) for sound effect generation.
dancer.js : dancer.js is a high-level audio API, usable with both Mozilla's Audio Data API and Webkit's Web Audio API with flash fallback, designed to make sweet ...
meSpeak.js (modulary enhanced speak.js) is a 100% client-side JavaScript text-to-speech library
