In the last years, we developed web applications requiring a large amount of JavaScript code. These web applications present adaptation requirements. In addition to platform-centric adaptation, applications have to dynamically react to external events like connectivity disruptions. Building such applications is complex and we faced sharp maintainability challenges. This paper presents h-ubu, a service-oriented component framework for JavaScript allowing building adaptive applications. h-ubu is used in industrial web applications and mobile applications. h-ubu is available in open source, as part of the OW2 Nanoko project.