Currently, Firefox and Thunderbird Extensions are very popular. Scripting an Extension is quite simple. All the information you need about the basic setup, you can find at the Mozilla Dev Wiki.
In this article I want to show how you can use Eclipse for developing Extensions.
First of all, you need to get Eclipse. You can download it at the official Page.
Since Firefox/Thunderbird-Extensions are JavaScript based, it’s strongly recommended to use the Web Tools Platform (WTP) Plugin. It’s already installed in the JEE Package and it supports JavaScript-Highlighting and Auto Completion. If you like to edit the XUL-Files (GUI-Elements) and modify the rdf-Files directly in Eclipse you will need the XUL Booster-Plugin for Eclipse.
After installing you can add a new Extension-Project in Eclipse simply by creating a new project and setting the path to your Extension-Directory.
In Windows Vista you will find it at this location:
C:\Users\<Your User Account-Name>\AppData\Roaming\Thunderbird or Mozilla Firefox\Profiles\<Your Profile-Name>\extensions\<Your Extensions-GUID>\
In Windows XP you will find it at this location:
C:\Users\<Your User Account-Name>\Applicationdata\Thunderbird or Mozilla Firefox\Profiles\<Your Profile-Name>\extensions\<Your Extensions-GUID>\
Please notice that it is indispensable to use a Jar-Free Manifest-Configuration. You can find information about this point in the Mozilla Wiki at the link above.
