How to create a Safari extension
If you know a little bit about HTML, CSS, and JavaScript you're already well equipped to create a Safari extension. Since Apple's documentation can seem intimidating, here's a tutorial to walk you through creating your first extension, using any custom CSS or JavaScript code you write.
http://rss.macworld.com/click.phdo?i=96fd93e0d1ffa30dfdc84f919b12409b
