Mozilla is the name of the open source browser created by, with funding and support from Netscape and its evil taskmaster, AOL. Netscape announced it was opening mozilla and founding on January 22, 1998, and the source was released on March 31, 1998. After more than four years of development, the long awaited version 1.0 was released on June 5, 2002. AOL has since turned over development to the Mozilla Foundation.

Mozilla attempts to be revolutionary in several ways:

  • It is open source. Mozilla wasn't the first open source browser, but it is certainly the most high profile and has the most momentum.
  • It was redesigned from the ground up. There should be a minimum of legacy cruft.
  • It is standards compliant. It attempts to match the existing standards exactly, in hopes of ending the one-upsmanship of proprietary features that has created the current mess that is the world wide web.
  • It is component-based. Microsoft deserves the credit for making COM-style component based programming mainstream, but mozilla has taken it cross platform with its XPCOM framework.
  • It has an cross platform XML-based user interface. The whole user interface is written in XUL, a type of XML, which makes it easy to customize and truly cross platform.

Mozilla and Netscape

Netscape Communicator, versions 6 and up, are based on mozilla, as are other projects such as phoenix, chimera, galeon and beonex. The new Netscape suite consists of the mozilla seamonkey framework repackaged, and bundled with extras like an integrated AIM compatible instant messenger and Netscape Radio.

Though mozilla is a complete rewrite, it mirrors the functionality of Netscape 4.x quite closely. It provides a web browser, webpage editor, and an e-mail and USENET news client, but it is missing a few minor features like roaming access, Palm synchronization and the calendaring client (though a new calendaring client based on open standards has been added recently). However, mozilla adds some useful components that Netscape never had, like an IRC client and a Cascading Style Sheet (CSS) editor.


Some of the features that make mozilla popular are:

  • Tabbed browsing - more that one page can be loaded into a single window and accessed by tabs at the top of the page; additionally, pages can be bookmarked together as a group of tabs
  • Image and cookie blocking - images and cookies can be blocked on a site by site basis; for example, all images and cookies from advertising sites like can be banned
  • Pop-up window blocking - or more accurately, unrequested pop-up window blocking -- this feature blocks so-called pop-up ads without interfering with most web applications that open new browser windows for legitimate purposes
The mozilla name

Mozilla was also the original code name for the classic Netscape browser, and was often used by the developers to describe it. There were always small references to Mozilla in the old Netscape: the user agent string identified the browser as Mozilla, not Netscape. Of course, almost all browsers now identify themselves as Mozilla, a holdover from when websites would inspect the user agent string and only serve the coolest content to Mozilla. There were easter eggs, too; typing about:mozilla would bring up a page from the "Book of Mozilla" and change the throbber animation to a fire-breathing lizard. The name itself comes from Mosaic + Godzilla (i.e. Mosaic killer), and was coined by Jamie Zawinski (jwz) when Netscape's primary competition was Spyglass Mosaic.