macOS how to add a menu into the Safari MenuBar or add a button into it’s MainWindow?

[xiaohuli170]

I want to develop a plugin with Safari. Now I wan to make a demo for add a button into it's MainWindow or menu into it's MenuBar. I have seen to Document WebKitPluginProgTopic and the sample:/Developer/Examples/Webkit/WebKitMoviePlugIn . But they didn't tell the full process of make a plugin with safari and how to add some menu or button in the safari window . Someone can give me some advice or simple code to resolve this problem, Thank you very much!