The invention enables the display of application-output data within application-output windows embedded in a web browser window. The application-output windows can be dynamically moved, resized and otherwise manipulated within the web browser window even when the application program providing the source of the application-output data is non-web enabled (e.g., legacy applications). The invention receives window attribute information associated with the application-output windows via a first virtual channel and displays application-output data received via a second virtual channel within the application-output windows, which are formed and/or modified using the window attribute information.