I'm writing a JavaScript Application that has to receive a huge amount of data from other users. It is not important if some of this data gets lost. Is there some way of using JavaScript WebSockets with UDP instead of TCP?
No, it's not possible to have UDP communication within JavaScript. Sorry.
It sounds like what you're waiting for is WebRTC which is working it's way through the standards process. WebSockets, as other people have pointed out, run over TCP as a result of initiating with an HTTP Upgrade.
The WebSockets protocol is over TCP only as currently defined.
You could do UDP with Flash if you are willing to use a RTMFP (Real Time Messaging Flow Protocol) server.
Sounds like the question is meant for client-side UDP, but since I ended up here...
You can do UDP in JavaScript on the server using the node.js dgram package.
If this question is still pending: I found a project called JNEXT and there is an example using UDP. The project itself seems to be paused but at least in Firefox it works (it doesn't work with Chrome and Opera). May be it is worth to look for it.
I think you can leverage Silverliht 4 technology. You can create a Silverlight 4 application to communicate with server and then enbamdded it to html page. Then your JavaScript can build TCP connections via Silverlight 4 application!
You could write a WebSocket server to serve as proxy/bridge between TCP/UDP.
You can use Autohotkey application, receiving UDP packets and showing Internet Explorer and, finally, sending the contents filling one html TEXTAREA and simulate clicking one run BUTTON that fires one event that process UDP data. I did it in my project XPlane Assistant.
来源：https://stackoverflow.com/questions/4657033/javascript-websockets-with-udp