WebSockets is an advanced technology that makes it possible to open an interactive communication session between the user's browser and a server. With this API, you can send messages to a server and receive event-driven responses without having to poll the server for a reply.
Documentation
- Writing WebSocket client applications
- A tutorial guide to writing WebSocket clients to run in the browser.
- WebSockets reference
- A reference to the client-side WebSocket API.
- Writing WebSocket servers (Needs Content)
- A guide to writing server-side code to handle the WebSocket protocol.
Tools
- Socket.IO: A powerful cross-platform WebSocket API for Node.js.
- WebSocket-Node: A WebSocket server API implementation for Node.js.
- A more extensive list of frameworks and libraries here
Related Topics
See also
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Version -76 support | 6 | 4.0 (2.0) | Not supported | 11.00 (disabled) | 5.0.1 |
| Protocol version 7 support | Not supported | 6.0 (6.0) Moz |
Not supported | Not supported | Not supported |
| Protocol version 10 support | 14 | 7.0 (7.0) Moz |
HTML5 Labs | ? | ? |
| Standard - RFC 6455 Support | 16 | 11.0 (11.0) | 10 | 12.10 | 6.0 |
| Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Version -76 support | ? | ? | ? | ? | ? |
| Protocol version 7 support | ? | ? | ? | ? | ? |
| Protocol version 8 support (IETF draft 10) | ? | 7.0 (7.0) | ? | ? | ? |
| Standard - RFC 6455 Support | 4.4 | 11.0 (11.0) | ? | 12.10 | 6.0 |
Gecko notes
WebSockets support in Firefox is continuing to track the evolving WebSocket specification. Firefox 6 implements version 7 of the underlying protocol, while Firefox 7 implements version 8 (as specified by IETF draft 10). Firefox mobile received WebSocket support in Firefox mobile 7.0.
Gecko 6.0
Prior to Gecko 6.0 (Firefox 6.0 / Thunderbird 6.0 / SeaMonkey 2.3), there was, incorrectly, a WebSocket object that some sites were thinking implied that WebSocket services were not prefixed; this object has been renamed to MozWebSocket.
Gecko 7.0
Starting in Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4), the network.websocket.max-connections preference is used to determine the maximum number of WebSocket connections that can be open at a time. The default value is 200.
Gecko 8.0
Starting in Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5), the deflate-stream extension to the WebSocket protocol has been disabled, since it's been deprecated from the specification drafts. This resolves incompatibilities with some sites.
Gecko 11.0
Prior to Gecko 11.0, both incoming and outgoing messages were limited to 16 MB in size. They may now be up to 2 GB in size. Note, however, that memory limitations (especially on mobile devices) make that a theoretical maximum, not a practical one. In reality, transfers of that size will fail on devices that don't have enough memory.
Additionally, ArrayBuffer send and receive support for binary data has been implemented.
Starting in Gecko 11.0, the WebSocket API is no longer prefixed.
Warning: Among other things, a key reason WebSockets was disabled by default in Firefox 4 and 5 is the discovery of a security issue in the protocol's design. This was fixed in Firefox 6 by implementing a newer version of the protocol that corrects the problem.