Code as simple as this allows you to share any video device, whether it's your webcam or your screen:
navigator.webkitGetUserMedia(
{video:{mandatory: {chromeMediaSource: 'screen'}}},
this.onUserMediaSuccess.bind(this),
this.onUserMediaError.bind(this)
);
Here's a screenshot of me sharing two screens between two Windows 8 computers. (click for larger view)
Here's a full screen view after double-clicking the thumbnail real-time view of the other PC's screen (click for larger view):
The demo leverages Openfire using the WebSockets and JingleNodes plugins, which uses a simple XMPP Jingle library. Interestingly, it has support for Jingle Relay Nodes to bridge the media when both peers cannot communicate directly with each other. No email registration is required so you can instantly try this demo without signing up for anything, though you do need to register a temporary username.
All you need is two PCs running Chrome version 26 stable or Firefox (Nightly build), both of which now support full desktop screen sharing. In Chrome, you have to enable "Enable screen capture support in getUserMedia()" via the chrome://flags URL for this to work.
Then simply open this URL https://webrtc.free-solutions.org:8443/webrtc/screen.html from the two PCs and register using two different user names and then call the other PC.
Go read the Ignite Realtime Blog for more info on the screen-sharing demo and then for more WebRTC fun, check out this demo with sample code! Lastly, be sure to check out the WebRTC Conference & Expo which will be in Atlanta, George in June.