Ben Taylor, Jesse Allison, and Yemin Oh have released NexusUI, a JS toolkit for easily designing musical interfaces for mobile apps and web browsers, with emphasis on rapid prototyping (nexusDrop) and integration with Max/MSP (nexusUp).
NexusUI can be used to integrate directly with the Web Audio API in the browser, or to communicate with Max, SuperCollider or Chuck via server-side applications.
NexusUI is mobile-friendly and multi-touch compatible. It enables large-scale collaborative performances by distributing interfaces through a browser — something that many people have at home, in their bag, or carry in their pocket.
NexusUI is available to download at no charge. NexusUI is licensed as open source software (New BSD License).
More information: NexusUI