Cruiser is an emerging library of useful albeit experimental JavaScript components that don't seem to exist in the bigger Ajax frameworks (or they can't be used independent from the framework). Emphasis is on modularity, cross-browser support, and lean, fast code. Components include:

• Parse: dynamic recursive descent LLk parser
• Behaviors: UJS framework via CSS stylesheet
• Specifications: behavior-driven testing
• RSD: Really Simple Data, a data format inspired by CSS
• Enumerable: A stand-alone library for dealing with collections.
• Module: A simple mechanism for code reuse.