Web development

Chirill Trescencov has gathered a great list of jQuery plugins. These are jQuery plugins developed to improve form usability and friendly user interface. Read More

I've prepared the list of useful extensions for FireFox browser. These extensions are very useful for web developer.
My favorite extension is "Web Developer" and "Live HTTP Headers" on bottom of below list.

Add N Edit Cookies
http://addneditcookies.mozdev.org/installation.html

Live HTTP Headers
http://livehttpheaders.mozdev.org/installation.html

QuickJava
https://addons.mozilla.org/firefox/1237/

TamperData
http://tamperdata.mozdev.org/installation.html

FireBug
https://addons.mozilla.org/firefox/1843/

Download Statusbar
https://addons.mozilla.org/firefox/26/

Web Developer
https://addons.mozilla.org/firefox/60/