ExtJs is a component framework. Due to it’s features described below, it is popular among developers around the world to create web application which looks similar to desktop application.
Browser compatibility :
HTML code generated by Extjs is compatible across popular browsers like Internet Explorer, Firefox, Safari, Chrome and so on.
Lots of active developers around the world are using it. Extjs has very active forum which is maintained by Sencha. So, online support turnaround time for any question is quick.
Now a days there are different platforms available and people around the world are using different devices like iPhone, ipad, android and so on. As a developer it is a challenge to maintain UI and functionality across different platforms. Applications written on Extjs runs on all platform without any glitch.
Rich set of API:
Extjs has rich set of API. We don’t need to look any third party plugin to solve our problem. For example, Extjs has grid feature which is very good. it has lots of other useful UI components available which you can find on Sencha.
Extjs supports object orientation features like define classes and inheritance in a way that’s closer to classical inheritance and doesn’t require the prototype property.