Appreciating final presentation experience, I realize the cross-browser issue is critically important to the AJAX performance so I figure out web developing is not a single page story. Developing is not only about logical coding but also needed to care about the limitations and specialties in different environment. We need to take care from browser, communication, logic, and data. Browser will determine the performance of visualization and behavior action. Communication related to manage the information transmission between client and server side. Logic will decide the maintainability of the application controls. Data is related to the communication between physical and logic world. It looks a boundless studying but is a good challange.