>>713
参考書を買うのも一つの手かと思うけど。
http://piro.sakura.ne.jp/xul/xul.html

適当に貼っとく。
https://developer.mozilla.org/ja/DOM_Inspector

https://developer.mozilla.org/ja/Extensions
https://developer.mozilla.org/ja/Code_snippets
https://developer.mozilla.org/ja/Gecko_DOM_Reference

http://kittttttan.web.fc2.com/xul/extension5.html
http://google-mania.net/archives/213