This paper introduces our study of GUI for TV set based on a web browser. It will show how to get great efficiency when developing web related applications which uses web service APIs by taking advantage of web browser features. However, because current HTML standards do not grant access to TV functions, we have tried using WebSocket server. Used as a web service on TV, it allows not only to develop Web Browser based GUI, but even mobile devices to connect to the server and to use the TV functions provided through it. It also grants great benefit by allowing to share the HTML5 applications with both TV and mobile devices, thanks to the platform independency.