MVC pattern is usually used for large-scale B/S application development. It supplies a structured module, and realizes software development’s job-share as well as application’s modularization. This paper in depth studies a WIKI system’s design and realization in client’s browser, in the process of realization. It fully uses JavaScript and combines with MVC pattern. So it makes all the application program higher systematic. At the same time, it reduces the maintenance cost because of using divided template and increasing code reusability.