A web developer is a programmer who specializes in, or is specifically engaged in, the development of World Wide Web applications, or distributed network applications that are run over HTTP from a web server to a web browser.
Add-ons are small pieces of software that add new features or
functionality to your installation of Firefox. Add-ons can augment
Firefox with new features, foreign language dictionaries, or change its
visual appearance. Through add-ons, you can customize Firefox to meet
your needs and tastes.
https://addons.mozilla.org/en-US/firefox/addon/web-developer/
http://www.getfirebug.com/
https://addons.mozilla.org/en-US/firefox/addon/cookies-manager-plus/
http://www.greasespot.net/
http://www.colorzilla.com/firefox/
https://github.com/benmmurphy/jsdeminifier_xpi
http://chrispederick.com/work/user-agent-switcher/
https://addons.mozilla.org/de/firefox/addon/phoenix/
http://code.kliu.org/noredirect/
https://code.google.com/p/httpfox/
