Setting up an extension development environment - MDC. This article gives suggestions on how to set up your Mozilla application for extension development.
Unless otherwise specified, these suggestions apply to both Firefox and Thunderbird as well as SeaMonkey version 2.0 and above. Overview Create a development user profile to run your development firefox session; with special development preferences in about:config. Install some Firefox development extensions to your dev profile. Edit files in the extensions folder of your profile and restart the application with the dev profile. Extension Developer. JavaScript Debugger. DOM Inspector.