msg-rpc provides bidirectional RPC support over a simple message interface such as WebSocket. Tere are WebSocket examples based on socket.io and sockjs. It just has a simple sendMessage/onMessage interface, with no other dependencies. It supports not only normal RPC, but also RPC Service, which makes RPC pushable (i.e. the server can also send a request to the client and expect some kind of response).
MyRPC is a remote procedure call framework designed to easily connect heterogeneous systems. It features IDL-based client/server stub generation, multi-platform capability, binary protocol (no need for escaping of binary data, less overhead), support for various data types (like string, binary, signed and unsigned integer, float, list, struct, and enum), and exception support. It has no external dependencies.