Interactive system designs often require the use of rich graphical components whose capabilities go beyond the set of widgets provided by GUI toolkits. The implementation of such rich graphical components require a high programming effort that GUI toolkits do not alleviate. In this paper, we propose the Loa framework that allows both the specification of rich graphical components and their integration within running interactive applications. We illustrate the specification and integration with the Loa framework as part of a global process for the design of interactive systems.