FUEL is a JavaScript library designed to help developers build extensions using terminology and interfaces that are familiar to them. FUEL is new in Firefox 3.

FUEL is about making it easier for extension developers to be productive, by minimizing some of the XPCOM formality and adding some "modern" JavaScript ideas. We want to start with areas that will provide the most benefit.

FUEL has a fuelIApplication interface that implements all the functions of extIApplication. The library has also been implemented in Thunderbird ("STEEL") and in SeaMonkey ("SMILE").

Objects

extIApplication Objects

• extIApplication
• extIConsole
• extIEventItem
• extIEventListener
• extIEvents
• extIExtension
• extIExtensions
• extIPreference
• extIPreferenceBranch
• extISessionStorage

fuelIApplication Objects

• fuelIAnnotations
• fuelIApplication
• fuelIBookmark
• fuelIBookmarkFolder
• fuelIBookmarkRoots
• fuelIBrowserTab
• fuelIWindow

XPCOM

Although the FUEL Application object is preloaded into XUL scripts, it is not preloaded into JavaScript XPCOM code. The object needs to be accessed like any other XPCOM service:

var Application = Components.classes["@mozilla.org/fuel/application;1"].getService(Components.interfaces.fuelIApplication);