How do I develop an addon for Safari?

I want some personally developed JavaScript code to execute whenever I load a page in Safari. Seems like addblock for Safari does this. Anyone know how to do this?

Safari is not extensible. There's no addon framework for it. But yet there's adblock and verious other addons available for it, although Apple's Webkit and Safari developers discourage users from using them, calling them 'binary hacks'. Seems though some of these addons use InputManager, which isn't documented at all anywhere, at least for not for how people are using it to load scripts in Safari. I guess I'm going to have to backwards engineer to see how addblock does it, but before I do, I thought I'd ask around here. Anyone know?

From stackoverflow

• Input managers are a commonly (ab)used way of injecting arbitrary code into another application's runtime. Once you are there, you have to reverse-engineer enough of the application itself to figure out how to get the behavior you want; usually that involves method swizzling to replace parts of the application you are hacking. It's not documented because there's no API to document, but you can learn about the individual pieces (how to write an input manager in general, how method swizzling in Objective C works, how to use tools like class-dump) and then put it all together.

  What you are describing sounds like Greasemonkey though, and there are least one or two hacks already out there to enable Greasemonkey-like behavior in Safari. I'd suggest seeing if one of them meets your needs first.

  jin : Now I want to make a safari plugin with simbl , and I have read the Armchair Guide To Cocoa Reverse Engineering. but when implement the method - (void)load; how to use the plugin to get the safari DOM object ,just like PIC or Flash URL ? Thank you very much !