Hi,
Crocodile has just open-sourced our MSRP over WebSocket (see http://tools.ietf.org/html/draft-pd-msrp-websocket) Javascript stack. The project is hosted on Google Code: http://code.google.com/p/crocodile-msrp/
The stack is distributed using the MIT License and was developed and tested along side the Kamailio MSRP over WebSocket implementation.
Regards,
Peter