More precisely my goal is to create an add-on (or plug-in?) which is able to communicate with my main Cocoa application using something like the NSDistributedNotificationCenter. I need to be able to inject JavaScript code into the current webpage and get return values from the JS calls when my add-on receives the request to do so by my main application. Then I need to pass the return values back to my main application for processing.
Alternatively if there is a simple way to call JS in the active Firefox webpage and get return values that would also do the job.
If you want more info on why I want to do this, you can look at my other question: http://stackoverflow.com/questions/1711342/how-to-send-javascript-code-to-ie-using-c-net-3-5-run-it-then-get-a-string
Note that I'm not only interested in knowing how to make a Firefox add-on but also in everything I talked about above. For example, how to inject JS into the active webpage, etc.
I'd like guidance on what technologies to use, tutorials and sample code if possible. The best would be a sample Xcode project but I'm not counting on this :P
Thanks in advance!
N.B: I'm working on 10.4.