Zepto.js
Thomas Fuchs has created exactly what jQuery mobile should be — a lightweight framework that does away with a lot of the cross-platform cruft that weighs down jQuery, designed just for mobile. It also does away with all of the fake, timing-based animations that most javascript frameworks use and shifts animations and transitions to CSS3. It’s even got touch events!
What’s more, its zipped, minified size is just 2,368 bytes and it implements a large subset of functions from libraries such as jQuery and Prototype, along with touch-specific events such as tap(), doubleTap() and swipe().
Update: jQuery creator John Resig takes issue with the way Zepto’s marketing frames it as a drop-in replacement for jQuery when used with Mobile Webkit, estimating that Zepto implements just 15% of the jQuery API, and misses many critical bugs with older versions of the Webkit framework.
