Extension Developer's Extension


The Extension Developer's Extension exists to make life easier for Firefox extension developers. Testing JavaScript code, prototyping XUL layouts, and building XPI packages are all made easier by this extension. Install it and try it out!


Extension Builder

Build your extension's package (jar and xpi files), as well as install your working directory as an extension for development. Now provides most of the features of the popular bash build script, including rewriting chrome.manifest to use jar files.

install.rdf Editor

Why edit install.rdf by hand? Use this convenient GUI.

Javascript Shell

Jesse Ruderman's Javascript Shell allows you to run javascript interactively. In extensiondev you can also experiment with XPCOM in the shell, as well as set your scope to any open window or webpage (using enumerateWindows) to run javascript as if it were in that document. Try it online!

Javascript Environment

Jesse Ruderman's Javascript Environment allows you to run blocks of javascript code. Like the Javascript Shell, this version has chrome privileges, so you can use XPCOM objects. Useful for testing code snippets, or entire files! Try it online!

Live XUL Editor

The Live XUL Editor allows you to edit XUL with a realtime preview. Quickly prototype your XUL layout with ease! Try it online!

Live HTML Editor

Jesse Ruderman's Live HTML Editor allows you to edit HTML with a realtime preview. Try it online!

JRX: real-time JavaScript RegExp evaluator

Cüneyt Yýlmaz's JRX allows you to test regular expressions in real time. Try it online!

Interactive XPath Tester

The Interactive XPath Tester allows you to quickly test an XPath expression against an XML document. Based on a tool by Tony Chang. Try the original online!

Enable Debugging Prefs

Toggle several preferences useful for debugging in one quick click.

Reload All Chrome

Reload all chrome without caching. Useful for testing overlay changes without restarting.