Agile and systematic development is important in Web application methodology because clients expect their frequent requirement changes to be implemented rapidly and regularly. However, previous studies may not be suitable for such development.

In this paper we propose a methodology for agile and somewhat systematic development of Web application. The methodology includes models, tools, and an agile process. The models extended from UML focus on the behavior of Web application. The agile process aims to have quick-to-market property and adaptability to requirement changes. Tools including Process Manager and Web Modeler support process execution and modeling activity to guide developers in applying the process. An example of university assets management system and a comparison between our methodology and other processes are given to validate our methodology.