There has been some hype lately on Ext JS being renamed to Sencha, but it was a rebranding of the company behind this product, which proposes other libraries like Raphael (SVG-related). Ext JS is still available as a standalone product on Sencha’s website. Ext JS is released for free with its open source license adapt to other open source applications, but also as a commercial product, for commercial use.
Yii Web Programming Framework is a PHP 5 framework, mainly inspired by Prado. The goals of Yii are striving for high performance, achieved by simplicity of the design, and very loose coupling between the various components. Some of the features of Yii include the classic MVC implementation, database access infrastructure, and support for theming, caching and localization.
Yii is released under the BSD license, like Zend Framework, so there are no limitations to its use in open source or commercial projects.
When using the provided ExtController as the superclass of the Yii application’s SiteController, the XML models are readily integrated and instantiated as Ext JS objects, without the need to include lots of .js files and event hooks.
In the Ext4Yii documentation, there are various examples of bootstrapping Ext JS widgets using these higher-level models, which deal with layout elements and forms. There are more advanced features included like AjaxMethods, which allows to call a registered PHP function via AJAX from the client side.
Learning a new modeling language can be complex, especially with verbose XML. Fortunately, there is a bundled plug-in for the NetBeans IDE which provides code completion for Ext4Yii. Even if you’re not a fan of IDEs, they sometimes are very handy in providing a rapid solution to bootstrap new tools like Ext4Yii.