The rapid development of the wireless communication technologies, including wireless sensors, intelligent mobile devices, and communication protocols, has led to diverse mobile devices of accessing various context-aware systems. Existing context-aware systems only focus on characterize the situation of an entity to exhibit the advantage of contextual information association. The contextual information can represent semantic implications to provide decidable reasoning services, but it has no mechanism to facilitating the interoperability and reusability among heterogeneous context-aware systems and various mobile devices. This study addresses these issues developing a Multi-layer Context Framework (MCF) that integrates Web 2.0 technologies into context-aware system for supporting ubiquitous mobile environment. The proposed MCF includes context sensor layer, context information layer, context service layer, context representation layer, mobile device layer, and context-aware mobile Web 2.0 application layer. To demonstrate the feasibility of the infrastructure, a Mobile Web 2.0-based Context-aware Attendance Monitoring System (MWCAMS) is implemented with ZigBee devices to provide continuous and context-aware monitoring of employee attendance status.