This page contains links to documentation for the approach to developing extensions for Gecko-based applications which uses:
- XUL overlays to specify the interface
- APIs available to privileged code, such as
tabbrowserand JavaScript modules, to interact with the application and content.
Prior to Firefox 4, and the Gecko 2 engine that powers it, this was the only way to develop extensions. This methodology has largely been superseded by restartless extensions, and the Add-on SDK, which is built on top of them. The privileged JavaScript APIs described here can still be used in these newer types of add-ons.
XUL School
XUL School is a comprehensive add-on development tutorial, focusing on Firefox extension development but mostly applicable to other Gecko-based applications.
More resources
- Setting up your environment
- Setting up the application for extension development.
- XUL
- Tutorials and reference for the user interface language used by XUL extensions.
- Code snippets
- Sample code for many of the things you'll want to do.
- Installing extensions
- How to install an extension by copying the extension files into the application's install directory.
- Firefox add-ons developer guide
- A guide to developing overlay extensions.
- JavaScript code modules
- JavaScript modules available to extension developers.
- Extension preferences
- How to specify the preferences for your extension that will appear in the Add-ons Manager.
- Extension packaging
- How extensions are packaged and installed.
- Binary Firefox extensions
- Creating binary extensions for Firefox.