This example implements a simple chat client and server. Using server-initiated updates, you can easily push events from one user to other users. Server-initiated updates are implemented using Ajax long polling or HTML5 WebSockets.
It also illustrates nice benefits of a class-based approach to web application development: you can easily instantiate the same widget class multiple times. The SimpleChatClient widget may be reused just as you reuse basic Wt widgets such as a push button.
The chat application is also available as a Widget which can be embedded in another page (very much like how you integrate a Google Maps widget inside another application). You could embed the chat in a homepage as follows:
<div id="chat"></div> <script src="//www.webtoolkit.eu/wt/examples/simplechat/chat.js?div=chat"></script>
This uses Cross-Origin Ajax/WebSocket requests (if the browser supports this, falling back to old tricks if not) to communicate from a HTML origin page to a server hosting the Widget possibly from a different domain.