Extjs4---常见错误集合

1、Uncaught TypeError: Cannot read property ‘dom’ of null

原因：如果代码段没有放入Ext.onReady中

2、Uncaught TypeError: Cannot call method 'hasOwnProperty' of undefined

参考这篇文章：Extjs4---Uncaught TypeError: Cannot call method 'hasOwnProperty' of undefined

3、Cannot read property 'addCls' of null

参考文章：Extjs4---Cannot read property 'addCls' of null

4、Uncaught TypeError: Cannot call method 'substring' of undefined

参考文章：Extjs4---Uncaught TypeError: Cannot call method 'substring' of undefined