An information processing system is provided that simplifies a logout procedure in an information processing apparatus that has a Web browser that operates together with a Web server that serves as an external apparatus, while maintaining the operational feel of the Web browser. To accomplish this, in the present information processing system, the Web server is notified of a user instruction input via an operation screen of the Web browser provided from the Web server as an event. Here, the Web server analyzes the notified event, and if this event is a logout request, the Web server executes processing for logging out of the Web server, and also notifies the Web browser of the logout request. The Web browser executes processing for logging out of the Web browser upon receipt of the logout request from the Web server.