vX is a set of functions all designed with size first, and functionality second. It started out as a single function for just Ajax, but is now has most of the features necessary in JS libraries.

Currently, the whole framework, including Ajax, Events, URL Encoding, Animation (including Fading), Namespacing, JSON Serialization, JSON Parsing, Document onReady, HTML entities encode/decode, Array Index, Function binding, Sliding animations, Ninja mode, Get Elements By Class Name, Object Extending, Templating, Queueing, Class Manipulation and more. is under 3kb total.

Try out the demos at: http://vxjs.googlecode.com/svn/trunk/test.htm

Build your own at: http://vxjs.googlecode.com/svn/trunk/build.htm

Find some useful plugins for vX at: http://vxjs-plugins.googlecode.com/

Documentation: http://code.google.com/p/vxjs/wiki/vxCore