What ==A short description== Extensions are small addons to a Mozilla product, such as Firefox or Thunderbird, that can extend the functionality of the browser to meet the user's needs. ==A longer detailed discussion== Extensions allow a user to enhance their Mozilla product to meet their personal requirements without the core product being too bloated. It can be anything from a toolbar button to a small icon on the status bar to another addon to the right-click menu. Extensions can be created by anyone that has the the knowledge of the following extension-related technologies: * XPI — Cross-Platform Installer module* JavaScript – The primary language of Mozilla Browsers* XUL (XML User Interface Language) – Used to define the UI (User Interface) and interaction with user.* DOM (Document Object Model) – Used to change XUL in real-time or to edit HTML that is currently loaded* CSS (Cascading Style Sheets)* XPCOM/XPConnect Extensions are installed via an [http://en.wikipedia.org/wiki/XPInstall XPInstall] module. ==Relevant resources== * [http://developer.mozilla.org/en/docs/Extensions MDC Extension Page]* [http://developer.mozilla.org/en/docs/Building_an_Extension Tutorial on how to build an Extension]* [http://developer.mozilla.org/en/docs/Extension_Frequently_Asked_Questions Extension Frequently Asked Questions]* [http://kb.mozillazine.org/Setting_up_extension_development_environment Setting up extensiondevelopment environment]* [http://developer.mozilla.org/en/docs/Extension_Packaging Extension Packaging]* [http://developer.mozilla.org/en/docs/Creating_Custom_Firefox_Extensions_with_the_Mozilla_Build_System Creating Custom Firefox Extensions with the Mozilla Build System]* [http://developer.mozilla.org/en/docs/Category:Extensions Articles about Extensions] ==Examples of code or other relevent artifacts== * [http://developer.mozilla.org/en/docs/Extension_Code_Snippets:Tabbed_Browser Tabbed Browser code] - snippet of code to help work with Firefox's tabbed browser.* [http://kb.mozillazine.org/Category:Example_code MozillaZine Example Code] ==Newsgroups, mailinglists, IRC channels, etc. relevant to the technology== * [https://lists.mozilla.org/listinfo/dev-extensions Mailing List]* [news://news.mozilla.org/mozilla.dev.extensions News Group]* [http://groups.google.com/group/mozilla.dev.extensions Google Group]* [http://groups.google.com/group/mozilla.dev.extensions/feeds Web Feed from Google Groups]* [irc://irc.mozilla.org/%23extdev IRC Channel]* [http://forums.mozillazine.org/?c=11 MozillaZine Forum]* [http://developer.mozilla.org/en/docs/Extensions:Community Extensions Community] ==Extensions== * [http://ted.mielczarek.org/code/mozilla/extensiondev/ Extension Builder] - an extension to help build an extension* [http://ted.mielczarek.org/code/mozilla/extensionwiz/ Firefox/Thunderbird Extension Wizard] - Generates an extension skeleton to meet your needs* [http://developer.mozilla.org/en/docs/Venkman Venkman] - Mozilla-based JavaScript debugger* [https://addons.mozilla.org/firefox/ Extension Downloads] - download thousands of extensions to meet your personal needs