Does an open sound control library exists for javascript? I cant seem to find any information on this.
I think a JavaScript OSC library, that works in the conventional way (e.g. using a UDP or TCP transport) is not possible due to the lack of low-level networking functionality provided in current browser-based implementations of the JavaScript. Cross-domain scripting limitations would also limit the usefulness of a browser-based OSC implementation IMO.
JavaScript OSC is possible by using custom XPCOM components, but at best, such solutions are going to be browser-specific.
One possibility might be to run OSC over a higher-level protocol. OSC over JSONP springs to mind as a potential area for exploration. Something similar to the MaxJax project, which implements OSC for the Python Twisted web server.