Abstract: Software testing is a difficult task and testing Web applications may be more difficult, due to their characteristics. Web application is an interactive one since it came into being. How to model and test Web interactions is a challenge in software engineering. Web navigation models are useful to clarify requirements and specify implementation behaviors. Web frameset and Web browser’s interactions are wildly used in today’s Web applications. The behaviors of Web frameset and Web browser interactions changed the traditional Web navigation and influence the functionalities of Web applications. In this study, we took Web frameset and Web browser’s interactions into account and proposed an approach to modeling the Web application’s navigation and generating tests with Web framesets and browser’s interactions. The construction formal semantics of structure composition of Web frameset is give out. Based on the formal semantics, the Web navigation with Web framesets is modeled. The Extended Browser Loading Model with Web frameset (EBLM) and the extended FSM is employed to formalize the navigation models with Web framesets and browser’s interactions and a FSM Test-Tree (FSM-TT) is constructed using present construction algorithm. At last, test generation is given out which satisfies the corresponding coverage criteria. This study resolves the following research problems: (1) propose an approach to modeling Web applications with Web framesets and Web browser’s interactions, (2) give the formal construction semantics of Web frameset and (3) formalize the navigation model and generating tests.