Ext JS can be said as a great helper for developers because it enables them to develop structured codes, allows to use libraries without any least possibility of overwriting. This is accomplished with Namespaces. Namespaces get into Class name grouped packages using dot-notation (.).
The power of Ext JS rests in its component design. The component design is set in such a way that default components can be extended and those can be re-used as your need without any effort. Another gain offered by Ext JS is that by combining one or more default components, a new component can be created.
Now, what all include in the Framework of Ext JS? It includes components such as dialogue boxes, menu bars, drop-down menus, panels and much more. Each has its own Configs, methods, CSS classes etc…
These are the very few basic features of Ext JS. When it is explored in a deep sense, it includes a long array of attributes which are very helpful for developers.