In a new post at his Steamclock Software blog, Nigel Brooke writes how Apple has added new Objective-C to Javascript bridging to WebKit:
"This new API supports straightforward embedding of the JavaScriptCore interpreter into native Objective-C projects, including reading and writing variables and object members with appropriate type coercion, calling methods on JavaScript objects, and directly binding Objective-C objects into JavaScript."
The API performs its bridging using Objective-C protocols, enabling you to bind JavaScript calls to Objective-C implementations. If you'd like to give the tech a test, Brooke has posted a working