Smart Browser is a framework that supports the easy integration of customized background services within a Web browser. The framework utilizes a set of extendable XML message schemas to communicate between the browser and the background services. Based on this framework, a set of background services are integrated into Firefox browser. These services can bring the intelligence of crowd and machine, which are usually logic complicated, data intensive and computing complex, to each end user by utilizing light weighted and daily used browser. It's obvious that applications built on this framework can improve users' experiences when surfing the Web.