What's New in Safari Extensions

Safari Extensions can add buttons to the Safari toolbar, display a bar with custom content, or modify the appearance of a web page - all with standard HTML, CSS, and JavaScript. See how easy it is to get started with Safari's built-in Extension Builder, and how to create an extension that can execute scripts, apply CSS styles, and display context menus. Discover new user interface components for extensions such as popovers, and learn to leverage additions to the Extensions API to invoke Safari Reader, detect how users are interacting with Safari, and more.

WWDC 2011 - macOS