Preferences

The preference system makes it possible to store data for Mozilla applications using a key/value pairing system. These articles provide information about how to use the preference system.

Documentation

Preferences system
An introduction to using the preference system in Mozilla.
XUL School: Handling preferences
The XUL School tutorial chapter on preferences.
Mozilla preference reference
A reference guide to all Mozilla preferences; currently a work in progress.
A brief guide to Mozilla preferences
An introductory guide to where preferences are stored and other useful information about the core preference system.
Using preferences from application code
Firefox 6 introduced static functions for accessing preferences efficiently from within application code. This API is not available for add-ons, but if you're working on a Gecko application, this API is the preferred way to access preferences.
Mozilla networking preferences
A guide to key networking-related preferences.
Mozilla preferences for uber-geeks
A guide to preferences that only truly elite geeks should play with.

Examples

Code snippets
Preference-related code snippets.
Adding preferences to an extension
How to add preferences to an existing extension.