Ext JS is a cross-browser JavaScript library for building rich internet applications. It includes:
* High performance, customizable UI widgets
* Well designed and extensible Component model
* An intuitive, easy to use API
* Commercial and Open Source licenses available
http://extjs.com/products/extjs/
Ext Core is a cross-browser JavaScript library for building dynamic web pages. It includes:
* High performance, lightweight
* Clear, maintainable code
* An intuitive, easy to use API
* MIT Open Source licensed