Performance of many Web sites depends on the load on the site at peak time under varying conditions. Performance testing is normally conducted in a reasonably simulated environment with the help of performance testing tools. However, performance of a Web site depends on various parameters and each parameter must be tested under varying stress levels. It is not possible to draw a common denominator for performance parameters to test the Web site due to complexity of Web sites. Different parts of the Web site must be tested with different parameters under varying condition and stress level. In such circumstances, it is necessary to decompose the Web site into many components, which represents the behavior of various business components. These business components are mapped to various objects that truly represent the behavior and structure of the part of the web site. These objects are subjected to performance testing with different parameters and stress levels. This paper addresses the new testing process, which uses the concept of decomposing the behavior of the Web site into testable components, which are mapped onto testable objects. These testable objects are subjected to performance testing under varied performance parameters and stress levels.