Justin Ireland has posted an article to his blog about creating real-time interfaces for your sites using the combination of HTML, CSS and Javascript to connect to a physical interface on the backend.
Physical interfaces such as button panels or remote controls have many disadvantages. Panel controls require a dedicated display for feedback and physical access to a fixed location. IR remote controls offer only one-way communication with limited feedback and can become difficult to manage for multiple devices. [...] We propose a new type of solution to address these issues and bring simplified management and control to a broader market through embedded virtual interfaces.
He lays out the structure of the application, some of the issues that could come up in the connection (using COMET and Websockets). His proof of concept is a connection to a HDMI switch that can be talked to through an embedded controller via a simple interface.