The study proposed will investigate the effects of functional control on online consumers’ attitude formation. Functional control is an interactive interface feature that allows consumers to virtually try different functions of online products. An attitude formation model for analyzing and assessing the influences of functional control is proposed based on existing theories of vividness and interactivity, which are the two fundamental technological characteristics of functional control. The model suggests that functional control has direct effects on both attitudes toward online product presentation and attitudes toward products themselves, and that attitudes toward different online product presentation partly mediate the effects of functional control on attitudes toward products. A laboratory experiment has been designed to test the model. We expect that the results of the study will identify particular areas deserving attention for applying functional control to improve e-commerce environments.