With a set of customizable user interface widgets similar to those found in desktop operating systems, an effective data binding model, a comprehensive programming interface. This book would have been quite useful when i started learning ext js, but even now it covers parts of ext js that i havent used yet. Senchas technologies first became of interest to andrew more than three years ago. If you use gpl software and dont modify it, you can use it commercially the way you like it. Developers who are already familiar with extjs will find practical guidance and numerous examples covering most of the librarys features and components, that can be used as a solid foundation to build upon when creating rich internet applications. Jorge has over 16 years of experience as a software developer and has also worked creating web applications, search engines, and automaticcontrol.