Gina at Lifehacker posted a really nice rundown of what goes into making a Firefox extension:
The meat of a Firefox extension is simply Javascript – the not-very-mysterious stuff of bookmarklets and regular old web pages – and a markup language called XUL (pronounced “zool.”) To build your own, you’ll need some Javascript know-how, comfort editing XML files, and a healthy curiosity about bending your favorite web browser to your will.
Check it out, then make something awesome and tell us about it in the comments.
How to build a Firefox extension (Gina@Lifehacker)- Link
How to create Firefox extensions (Eric Hamiter) – Link
The Official Building an Extension Guide – Link
