Ext Core是一个跨浏览器，分离自Ext UI的Javascr ipt框架，类似于jQuery，Prototype，Mootools等框架-Ext Core is a cross-browser, the Javascr ipt isolated from Ext UI framework, similar to the jQuery, Prototype, Mootools and other frameworks

ExtJS Core参考手册，对了解ExtJS Core有很好的参考价值。