Firefox

This article is about the web browser. For the operating system, see Firefox OS. For other uses, see Firefox (disambiguation).

Mozilla Firefox

Firefox 29.0 on Windows 8.1
Developer(s)	Mozilla Foundation and contributors Mozilla Corporation
Initial release	September 23, 2002 (2002-09-23)
Stable release	Standard 133.0.3  / December 10, 2024 (December 10, 2024) Extended support release 1 128.5.2esr  / December 12, 2024 (December 12, 2024) Extended support release 2 115.18.0esr / November 26, 2024 (2024-11-26)
Preview release	Beta & developer edition 134.0b9  / December 11, 2024 (December 11, 2024) Nightly 135.0a1  / November 25, 2024 (November 25, 2024)
Repository	hg.mozilla.org/mozilla-central/
Written in	C++, JavaScript, C, Cascading Style Sheets, XUL, XBL
Engines	Gecko, SpiderMonkey
Operating system	Windows, OS X, Linux, Android, Firefox OS, FreeBSD, NetBSD, OpenBSD, OpenIndiana
Size	22 MB: Windows 44 MB: OS X 27–28 MB: Linux 22 MB: Android 510 MB: source code (uncompressed)
Standard(s)	HTML5, CSS3, RSS, Atom
Available in	79 languages
Type	Web browser Feed reader Mobile web browser
License	MPL
Website	mozilla.org/firefox

Mozilla Firefox (known simply as Firefox) is a free and open-source web browser developed for Windows, OS X, and Linux, with a mobile version for Android, by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. Firefox uses the Gecko layout engine to render web pages, which implements current and anticipated web standards.

As of February 2014, Firefox has between 12% and 22% of worldwide usage, making it the third most popular web browser, according to different sources. According to Mozilla, Firefox counts over 450 million users around the world. The browser has had particular success in Indonesia, Iran, Germany, and Poland, where it is the most popular browser with 55%, 46%, 43%, and 41% of the market share, respectively.

History

Main article: History of Firefox

The Firefox project began as an experimental branch of the Mozilla project by Dave Hyatt, Joe Hewitt and Blake Ross. They believed the commercial requirements of Netscape's sponsorship and developer-driven feature creep compromised the utility of the Mozilla browser. To combat what they saw as the Mozilla Suite's software bloat, they created a stand-alone browser, with which they intended to replace the Mozilla Suite. On April 3, 2003, the Mozilla Organization announced that they planned to change their focus from the Mozilla Suite to Firefox and Thunderbird.

Phoenix 0.1 screenshot on Windows XP.

The Firefox project has undergone several name changes. Originally titled Phoenix, it was renamed due to trademark issues with Phoenix Technologies. The replacement name, Firebird, provoked an intense response from the Firebird database software project. In response, the Mozilla Foundation stated that the browser would always bear the name Mozilla Firebird to avoid confusion. After further pressure, on February 9, 2004, Mozilla Firebird became Mozilla Firefox, often referred to as Firefox. Mozilla prefers the Firefox abbreviation Fx or fx, though it is often abbreviated as FF. The Firefox project went through many versions before version 1.0 was released on November 9, 2004.

Features

Main article: Features of Firefox

Features include tabbed browsing, spell checking, incremental find, live bookmarking, Smart Bookmarks, a download manager, private browsing, location-aware browsing (also known as "geolocation") based on a Google service and an integrated search system that uses Google by default in most localizations. Functions can be added through extensions, created by third-party developers, of which there is a wide selection, a feature that has attracted many of Firefox's users.

Additionally, Firefox provides an environment for web developers in which they can use built-in tools, such as the Error Console or the DOM Inspector, or extensions, such as Firebug.

Standards

The result of the Acid3 test on Firefox 17

Firefox implements many web standards, including HTML4 (partial HTML5), XML, XHTML, MathML, SVG 1.1 (partial), CSS (with extensions), ECMAScript (JavaScript), DOM, XSLT, XPath, and APNG (Animated PNG) images with alpha transparency. Firefox also implements standards proposals created by the WHATWG such as client-side storage, and canvas element.

Firefox has passed the Acid2 standards-compliance test since version 3.0. Mozilla had originally stated that they did not intend for Firefox to pass the Acid3 test fully because they believed that the SVG fonts part of the test had become outdated and irrelevant, due to WOFF being agreed upon as a standard by all major browser makers. Because the SVG font tests were removed from the Acid3 test in September 2011, Firefox 4 and greater scored 100/100.

Firefox also implements a proprietary protocol from Google called "Safe Browsing", used to exchange data related with phishing and malware protection.

Security

See also: Browser security

Firefox uses a sandbox security model, and limits scripts from accessing data from other web sites based on the same-origin policy. It uses SSL/TLS to protect communications with web servers using strong cryptography when using the HTTPS protocol. It also provides support for web applications to use smartcards for authentication purposes.

The Mozilla Foundation offers a "bug bounty" (up to 3000 USD cash reward and a Mozilla T-shirt) to researchers who discover severe security holes in Firefox. Official guidelines for handling security vulnerabilities discourage early disclosure of vulnerabilities so as not to give potential attackers an advantage in creating exploits.

Because Firefox generally has fewer publicly known unpatched security vulnerabilities than Internet Explorer (see Comparison of web browsers), improved security is often cited as a reason to switch from Internet Explorer to Firefox. The Washington Post reported that exploit code for known critical unpatched security vulnerabilities in Internet Explorer was available for 284 days in 2006. In comparison, exploit code for known, critical security vulnerabilities in Firefox was available for nine days before Mozilla issued a patch to remedy the problem.

A 2006 Symantec study showed that, although Firefox had surpassed other browsers in the number of vendor-confirmed vulnerabilities that year through September, these vulnerabilities were patched far more quickly than those found in other browsers – Firefox's vulnerabilities were fixed on average one day after the exploit code was made available, as compared to nine days for Internet Explorer. Symantec later clarified their statement, saying that Firefox still had fewer security vulnerabilities than Internet Explorer, as counted by security researchers.

In 2010 a study of the National Institute of Standards and Technology (NIST) based on data compiled from the National Vulnerability Database (NVD), Firefox was listed as the fifth most vulnerable desktop software, with Internet Explorer as the eighth, and Google Chrome as the first.

InfoWorld has cited security experts saying that, as Firefox becomes more popular, more vulnerabilities will be found, a claim that Mitchell Baker, president of the Mozilla Foundation, has denied. "There is this idea that market share alone will make you have more vulnerabilities. It is not relational at all," she said.

In October 2009, Microsoft's security engineers acknowledged that Firefox was vulnerable to a security issue found in the 'Windows Presentation Foundation' browser plug-in since February of that year. A .NET Framework 3.5 SP1 Windows Update had silently installed the vulnerable plug-in into Firefox. This vulnerability has since been patched by Microsoft.

As of February 11, 2011, Firefox 3.6 had no known unpatched security vulnerabilities according to Secunia. Internet Explorer 8 had five unpatched security vulnerabilities, the worst being rated "Less Critical" by Secunia. Mozilla claims that all patched vulnerabilities of Mozilla products are publicly listed.

On January 28, 2013, Mozilla was recognized as the most trusted internet company for privacy in 2012. This study was performed by the Ponemon Institute and was a result of a survey from more than 100,000 consumers in the United States.

In February 2013, plans were announced for Firefox 22 to disable third-party cookies by default. However, the introduction of the feature was then delayed so Mozilla developers could "collect and analyze data on the effect of blocking some third-party cookies." Mozilla also collaborated with Stanford University's "Cookie Clearinghouse" project to develop a blacklist and whitelist of sites that will be used in the filter.

Version 23, released in August 2013, followed the lead of its competitors by blocking iframe, stylesheet, and script resources served from non-HTTPS servers embedded on HTTPS pages by default. Additionally, JavaScript could also no longer be disabled through Firefox's preferences, and JavaScript was automatically re-enabled for users who upgraded to 23 or higher with it disabled. The change was made due to its use across the majority of websites, the potential repercussions on non-experienced users who are unaware of its impact, along with the availability of extensions such as NoScript, which can disable JavaScript in a more controlled fashion. The following release added the ability to disable JavaScript through the developer tools for testing purposes.

Telemetry

In Firefox versions prior to 7.0, an information bar appears on the browser's first start asking users whether they would like to send performance statistics, or “telemetry”, to Mozilla. It is enabled by default in development versions of Firefox, but not in release versions. According to Mozilla's privacy policy, these statistics are stored only in aggregate format, and the only personally identifiable information transmitted is the user's IP address.

Localizations

Main article: Mozilla localizations

Firefox 22 in the Portuguese language

Firefox is a widely localized web browser. The first official release in November 2004 was available in 24 different languages and for 28 locales, including British English/American English, European Spanish/Argentine Spanish and Chinese in Traditional Chinese characters/Simplified Chinese characters. The currently supported 31.0 and 31.0esr versions are available in 89 locales (79 languages).

Platform availability

Firefox for desktop is available and supported for Windows, OS X, FreeBSD, and Linux, while Firefox for mobile is available for Android. In September 2013, the Windows 8 Touch interface, optimized for touchscreen use, was introduced on the "Aurora" release channel; however, the project has since been cancelled as of March 2014, citing a lack of user adoption of the beta versions.

• 
  Firefox 24 running on Ubuntu 13.04
• 
  Firefox 30 on OS X Mavericks
• 
  Firefox Aurora 26 Windows 8 Touch version on Windows 8
• 
  Firefox for mobile 14 on Android

Firefox has also been ported to SkyOS, and an unofficial rebranded version called Timberwolf has been available for AmigaOS 4.

Release history

Main article: History of Firefox § Release history

Firefox running on a digital advertising sign (identifiable by its connection failure message)

Mozilla provides development builds of Firefox in distribution channels named, in order of most to least stable, "Beta", "Aurora", and "Nightly". As of 10 June 2014, Firefox 31 beta is in the "Beta" channel, Firefox 32 alpha is in the "Aurora" channel, and Firefox 33 pre-alpha is in the "Nightly" channel.

Firefox for mobile

Main article: Firefox for mobile

Firefox for mobile 14.0 on Android

Firefox for mobile, codenamed Fennec, is a web browser for smaller non-PC devices, mobile phones and PDAs. It was first released for the Nokia Maemo operating system, specifically the Nokia N900, on January 28, 2010. Version 4 for Android and Maemo was released on March 29, 2011. The browser's version number was bumped from version 2 to version 4 to synchronize with all future desktop releases of Firefox since the rendering engines used in both browsers are the same. Version 7 was the last release for Maemo on the N900. The user interface is completely redesigned and optimized for small screens, the controls are hidden away so that only the web content is shown on screen, and it uses touchscreen interaction methods. It includes the Awesomebar, tabbed browsing, Add-on support, password manager, location-aware browsing, and the ability to synchronize with the user's computer Firefox browser using Firefox Sync.

Extended Support Release

See also: History of Firefox § Extended Support Release, and Long-term support

Firefox Extended Support Release, abbreviated to Template:Dabbr, is a version of Firefox for organizations and other groups that need extended support for mass deployments. Each ESR release, based on the regular version released at the same time, is supported for approximately one year. Unlike the regular ("rapid") releases, ESRs are not updated with new features and performance enhancements every six weeks, but rather are updated with only high-risk-reduction or high-impact security fixes or major stability fixes with point releases, until the end of the ESR cycle. As of July 2014, 31.x is the supported version of ESR, with 38.x scheduled to be released with Firefox rapid release 38 in May 2015; support for ESR versions 10.x and 17.x has been discontinued, with 24.x to be discontinued in October 2014.

System requirements

Firefox source code may be compiled for various operating systems; however, officially distributed binaries are provided for the following:

Recommended hardware and required software

	Windows	Linux desktop	OS X	Android
CPU	Pentium 4 or newer with SSE2		Any Intel CPU	ARMv7 CPU (ARMv6 also works)
Memory (RAM)	512 MB			384 MB
Hard disk drive free space	200 MB			24 MB
Operating system version	XP SP2 (desktop) Server 2003 SP1 (server) or newer	Kernel 2.2.14 or newer with: GTK+ 2.18 or newer GLib 2.22 or newer Pango 1.14 or newer X.Org 1.0 or newer (1.7 or newer recommended) libstdc++ 4.3 or newer	OS X 10.6 or newer	2.2 or newer

Display size (on mobile) must be at least 320 pixels high and 240 pixels wide.

OS support history

Operating system		Latest stable version	Support status
Microsoft Windows	XP SP2, Server 2003 SP1 and later	31.0 and 31.0esr	2004–present
	2000, XP (RTM, SP1), Server 2003 RTM	10.0.12esr and 12.0	2004–2013
	NT 4, 98, 98 SE, ME	2.0.0.20	2004–2008
	95	1.5.0.12	2004–2007
OS X	10.6 – 10.9	31.0 and 31.0esr	2009–present
	10.5 (Intel)	10.0.12esr and 16.0.2	2007–2013
	10.4 – 10.5 (PPC)	3.6.28	2005–2012
	10.2 – 10.3	2.0.0.20	2004–2008
	10.0 – 10.1	1.0.8	2004–2006
Linux	Desktop kernel 2.2.14 and newer (with some libraries)	31.0 (i686), 31.0 (x86_64), 31.0esr (i686) and 31.0esr (x86_64)	2004–present
	Android 2.2 and newer	31.0	2010–present
	Firefox OS	26.0	2013–present

Notes

• FreeBSD provides a regularly updated port of Firefox.
• Firefox 3.5.9 is the last version to work on HP-UX 11i, as packaged by Hewlett-Packard.
• Firefox 2.0 has been ported to RISC OS (i.e. not supported by Mozilla).
• In March 2014, Firefox for Metro project has been cancelled, although there is a beta release.

CPU architecture

Native 64-bit builds are officially supported on Linux and OS X, but not on Windows:

Operating system	32-bit support	64-bit support
Linux[a]	Yes
OS X[b]	Yes
Windows[c]	Yes	Nightly build

Notes

• ^[a] Linux: Mozilla made Firefox for 64-bit Linux a priority with the release of Firefox 4, labeling it as tier 1 priority. Since being labeled tier 1, Mozilla has been providing official 64-bit releases for its browser for Linux. Vendor-backed 64-bit support has existed for Linux distributions such as Novell-Suse Linux, Red Hat Enterprise Linux, and Ubuntu prior to Mozilla's support of 64-bit, even though vendors were faced with the challenge of having to turn off the 64-bit JIT compiler due to its instability prior to Firefox 4.

• ^[b] OS X: The official releases of Firefox for OS X are universal builds that include both 32-bit and 64-bit versions of the browser in one package, and have been this way since Firefox 4. A typical browsing session uses a combination of the 64-bit browser process and a 32-bit plugin process, because some popular plugins still are 32-bit.

• ^[c] Windows: The 32-bit and 64-bit versions of Windows Vista and Windows 7 can be used to run 32-bit Firefox. Mozilla does not currently support Win64 because many plug-ins do not yet support Win64 and other issues. Mozilla provides 64-bit versions for their Firefox nightly builds, however, the builds are not considered stable by Mozilla. In late 2012, Mozilla announced 64-bit Windows builds would be stopped but later reversed the decision.

Licensing

Firefox source code is free software, with most of it being released under the Mozilla Public License (MPL). This license permits anyone to view, modify, and/or redistribute the source code. As a result, several publicly released applications have been built from it, such as Netscape, Flock, Miro, Iceweasel, and Songbird.

In the past, Firefox was licensed solely under the MPL, then version 1.1, which the Free Software Foundation criticized for being weak copyleft, as the license permitted, in limited ways, proprietary derivative works. Additionally, code only licensed under MPL 1.1 could not legally be linked with code under the GPL. To address these concerns, Mozilla re-licensed most of Firefox under the tri-license scheme of MPL 1.1, GPL 2.0, or LGPL 2.1. Since the re-licensing, developers were free to choose the license under which they received most of the code, to suit their intended use: GPL or LGPL linking and derivative works when one of those licenses is chosen, or MPL use (including the possibility of proprietary derivative works) if they chose the MPL. However, on January 3, 2012, Mozilla released the GPL-compatible MPL 2.0, and with the release of Firefox 13 on June 5, 2012, Mozilla used it to replace the tri-licensing scheme.

The crash reporting service was initially closed source, but switched with version 3 from a program called Talkback to the open source Breakpad & Socorro.

Trademark and logo

See also: Mozilla Corporation software rebranded by the Debian project

The name "Mozilla Firefox" is a registered trademark; along with the official Firefox logo, it may only be used under certain terms and conditions. Anyone may redistribute the official binaries in unmodified form and use the Firefox name and branding for such distribution, but restrictions are placed on distributions which modify the underlying source code. The name "Firefox" derives from a nickname of the red panda.

Mozilla has placed the Firefox logo files under open-source licenses, but its trademark guidelines do not allow displaying altered or similar logos in contexts where trademark law applies.

Logo used for Iceweasel

There has been some controversy over the Mozilla Foundation's intentions in stopping certain open source distributions from using the "Firefox" trademark. Mozilla Foundation Chairperson Mitchell Baker explained in an interview in 2007 that distributions could freely use the Firefox trademark if they did not modify source-code, and that the Mozilla Foundation's only concern was with users getting a consistent experience when they used "Firefox".

To allow distributions of the code without using the official branding, the Firefox source code contains a "branding switch". This switch, often used for alphas of future Firefox versions, allows the code to be compiled without the official logo and name, and can allow a derivative work unencumbered by restrictions on the Firefox trademark to be produced. In the unbranded compilation the trademarked logo and name are replaced with a freely distributable generic globe logo and the name of the release series from which the modified version was derived.

Distributing modified versions of Firefox under the "Firefox" name requires explicit approval from Mozilla for the changes made to the underlying code, and requires the use of all of the official branding. For example, it is not permissible to use the name "Firefox" without also using the official logo. When the Debian project decided to stop using the official Firefox logo in 2006 (because Mozilla's copyright restrictions at the time were incompatible with Debian's guidelines), they were told by a representative of the Mozilla Foundation that this was not acceptable, and were asked either to comply with the published trademark guidelines or cease using the "Firefox" name in their distribution. Ultimately, Debian switched to branding their modified version of Firefox "Iceweasel", along with other Mozilla software.

Branding and visual identity

Early Firebird and Phoenix releases of Firefox were considered to have reasonable visual designs. Yet when compared to many other professional software packages it fell short. In October 2003, professional interface designer Steven Garrity wrote an article covering everything he considered to be wrong with Mozilla's visual identity. The page received a great deal of attention; the majority of criticism pointed out that as the software was open source, Garrity could have submitted patches to fix the problems.

Blue globe artwork is distributed with Firefox source code, and is explicitly not protected as a trademark

Shortly afterwards, the Mozilla Foundation invited Garrity to head up the new visual identity team. The release of Firefox 0.8 in February 2004 saw the introduction of the new branding efforts. Included were new icon designs by silverorange, a group of web developers with a long-standing relationship with Mozilla. The final renderings are by Jon Hicks, who had worked on Camino. The logo was later revised and updated, fixing several flaws found when it was enlarged.

The animal shown in the logo is a stylized fox, although "firefox" is usually a common name for the red panda. The panda, according to Hicks, "didn't really conjure up the right imagery" and wasn't widely known. Mozilla chose the logo to make an impression while not shouting out with overdone artwork. It had to stand out in the user's mind, be easy for others to remember, and stand out without causing too much distraction when seen among other icons.

The Firefox icon is a trademark used to designate the official Mozilla build of the Firefox software and builds of official distribution partners. For this reason software distributors who distribute modified versions of Firefox do not use the icon.

• Logo history
• Logo used for Firefox 1.0 – 3.0 from November 9, 2004 to June 29, 2009
  Logo used for Firefox 1.0 – 3.0 from November 9, 2004 to June 29, 2009
• 
  Logo used for Firefox 3.5 – 22.0 from June 30, 2009 to August 5, 2013
• 
  Logo used for Firefox 23 and after since August 6, 2013

• Other logos are also used for specific versions of the software
• 
  Logo of "Phoenix" and "Firebird" before being renamed as Firefox
• 
  The 2011 Aurora logo, used to represent an alpha release
• 
  The 2011 Nightly logo, used to represent nightly builds of pre-alpha versions
• 
  The 2013 Aurora logo
• 
  The 2013 Nightly logo
• 
  Minefield logo (former name for "nightly" Firefox)

Promotion

Firefox was adopted rapidly, with 100 million downloads in its first year of availability. This was followed by a series of aggressive marketing campaigns starting in 2004 with a series of events Blake Ross and Asa Dotzler called "marketing weeks".

Firefox continued to heavily market itself by releasing a marketing portal dubbed "Spread Firefox" (SFX) on September 12, 2004, It debuted along with the Firefox Preview Release, creating a centralized space for the discussion of various marketing techniques. A two-page ad in the December 16 edition of the New York Times, placed by Mozilla Foundation in coordination with Spread Firefox, featured the names of the thousands of people worldwide who contributed to the Mozilla Foundation's fundraising campaign to support the launch of the Firefox 1.0 web browser. SFX portal enhanced the "Get Firefox" button program, giving users "referrer points" as an incentive. The site lists the top 250 referrers. From time to time, the SFX team or SFX members launch marketing events organized at the Spread Firefox website. As a part of the Spread Firefox campaign, there was an attempt to break the world download record with the release of Firefox 3. This resulted in an official certified Guinness world record, with over eight million downloads. In February 2011, Mozilla announced that it would be retiring Spread Firefox (SFX). Three months later, in May 2011, Mozilla officially closed Spread Firefox. Mozilla wrote that "there are currently plans to create a new iteration of this website [Spread Firefox] at a later date."

In celebration of the third anniversary of the founding of the Mozilla Foundation, the "World Firefox Day" campaign was established on July 15, 2006, and ran until September 15, 2006. Participants registered themselves and a friend on the website for nomination to have their names displayed on the Firefox Friends Wall, a digital wall that will be displayed at the headquarters of the Mozilla Foundation.

The Firefox community has also engaged in the promotion of their web browser. In 2006, some of Firefox's contributors made a crop circle of the Firefox logo in an oat field near Amity, Oregon, near the intersection of Lafayette Highway and Walnut Hill Road. After Firefox reached 500 million downloads on February 21, 2008, the Firefox community celebrated by visiting FreeRice to earn 500 million grains of rice.

Other initiatives include Live Chat, a service Mozilla launched in 2007 that allowed users to seek technical support from volunteers. The service was later retired.

Performance

In December 2005, Internet Week ran an article in which many readers reported high memory usage in Firefox 1.5. Mozilla developers said that the higher memory use of Firefox 1.5 was at least partially due to the new fast backwards-and-forwards (FastBack) feature. Other known causes of memory problems were malfunctioning extensions such as Google Toolbar and some older versions of AdBlock, or plug-ins, such as older versions of Adobe Acrobat Reader. When PC Magazine compared memory usage of Firefox 2, Opera 9, and Internet Explorer 7, they found that Firefox used approximately as much memory as the other two browsers.

Softpedia noted that Firefox 1.5 took longer to start up than other browsers, which was confirmed by further speed tests. IE 6 launched more swiftly than Firefox 1.5 on Windows XP since many of its components were built into the OS and loaded during system startup. As a workaround for the issue, a preloader application was created that loaded components of Firefox on startup, similar to Internet Explorer. A Windows Vista feature called SuperFetch performs a similar task of preloading Firefox if it is used often enough.

Tests performed by PC World and Zimbra in 2006 indicated that Firefox 2 used less memory than Internet Explorer 7. Firefox 3 used less memory than Internet Explorer 7, Opera 9.50 Beta, Safari 3.1 Beta, and Firefox 2 in tests performed by Mozilla, CyberNet, and The Browser World. In mid-2009, Betanews benchmarked Firefox 3.5 and declared that it performed "nearly ten times better on XP than Microsoft Internet Explorer 7".

In January 2010, Lifehacker compared the performance of Firefox 3.5, Firefox 3.6, Google Chrome 4 (stable and Dev versions), Safari 4, and Opera (10.1 stable and 10.5 pre-alpha versions). Lifehacker timed how long browsers took to start and reach a page (both right after boot-up and after running at least once already), timed how long browsers took to load nine tabs at once, tested JavaScript speeds using Mozilla's Dromaeo online suite (which implements Apple's SunSpider and Google's V8 tests) and measured memory usage using Windows 7's process manager. They concluded that Firefox 3.5 and 3.6 were the fifth and sixth fastest browsers respectively on startup, 3.5 was third and 3.6 was sixth fastest to load nine tabs at once, 3.5 was sixth and 3.6 was fifth fastest on the JavaScript tests. They also concluded that Firefox 3.6 was the most efficient with memory usage followed by Firefox 3.5.

In February 2012, Tom's Hardware performance tested Chrome 17, Firefox 10, Internet Explorer 9, Opera 11.61, and Safari 5.1.2 on Windows 7. Tom's Hardware summarized their tests into four categories: Performance, Efficiency, Reliability, and Conformance. In the performance category they tested HTML5, Java, JavaScript, DOM, CSS 3, Flash, Silverlight, and WebGL – they also tested start up time and page load time. The performance tests showed that Firefox was either "acceptable" or "strong" in most categories, winning three categories (HTML5, HTML5 Hardware acceleration, and Java) only finishing "weak" in CSS performance. In the efficiency tests, Tom's Hardware tested memory usage and management. In this category, it determined that Firefox was only "acceptable" at performing light memory usage, while it was "strong" at performing heavy memory usage. In the reliability category, Firefox performed a "strong" amount of proper page loads. In the final category, conformance, it was determined that Firefox had "strong" conformance for JavaScript and HTML5. In conclusion, Tom's Hardware determined that Firefox was the best browser for Windows 7 OS, but that it only narrowly beat Google Chrome.

In June 2013, Tom's Hardware again performance tested Firefox 22, Chrome 27, Opera 12, and Internet Explorer 10. They found that Firefox slightly edged out the other browsers in their "performance" index, which examined wait times, Javascript execution speed, HTML5/CSS3 rendering, and hardware acceleration performance. Firefox also scored the highest on the "non-performance" index, which measured memory efficiency, reliability, security, and standards conformance, finishing substantially ahead of Chrome, the runner-up. Tom's Hardware concluded by declaring Firefox the "sound" winner of the performance benchmarks.

In January 2014, a benchmark testing the memory usage of Firefox 29, Google Chrome 34, and Internet Explorer 11 indicated that Firefox used the least memory when a substantial number of tabs were open.

Market adoption

See also: Usage share of web browsers

Usage share of web browsers according to StatCounter

Usage share of web browsers (November 2012 – StatCounter)

Downloads have continued at an increasing rate since Firefox 1.0 was released in November 2004, and as of July 31, 2009 Firefox had already been downloaded over one billion times. This number does not include downloads using software updates or those from third-party websites. They do not represent a user count, as one download may be installed on many machines, one person may download the software multiple times, or the software may be obtained from a third party. According to Mozilla, Firefox has more than 450 million users as of October 2012.

In July 2010, all IBM employees (about 400,000) were asked to use Firefox as their default browser.

Firefox was the second-most used web browser until December 2011, when Google Chrome surpassed it.

As of February 2014, Firefox was the third most widely used browser, with approximately 20% of worldwide usage share of web browsers. According to StatCounter, Firefox usage peaked in November 2009 and usage share remained stagnant until October 2010 when it lost market share, a trend that continued for over a year. Its first consistent gains in usage share since September 2010 occurred in February through May 2012 before declining to its lowest in October 2013 before then recovering slightly.

See also

• Firefox OS
• Mozilla Prism
• Timeline of web browsers
• Web browser history
• XULRunner

Further reading

• Cheah, Chu Yeow (2005). Firefox Secrets: A Need-To-Know Guide. O'Reilly. ISBN 0-9752402-4-2.
• Feldt, Kenneth C. (2007). Programming Firefox. O'Reilly. ISBN 0-596-10243-7.
• Granneman, Scott (2005). Don't Click on the Blue e!: Switching to Firefox. O'Reilly. ISBN 0-596-00939-9.
• Hofmann, Chris; Marcia Knous; John Hedtke (2005). Firefox and Thunderbird Garage. Prentice Hall PTR. ISBN 0-13-187004-1.
• McFarlane, Nigel (2005). Firefox Hacks. O'Reilly. ISBN 0-596-00928-3.
• Reyes, Mel (2005). Hacking Firefox: More Than 150 Hacks, Mods, and Customizations. Wiley. ISBN 0-7645-9650-0.
• Ross, Blake (2006). Firefox for Dummies. Wiley. ISBN 0-471-74899-4.

External links

• Official website for end-users
• Firefox Nightly Builds
• Firefox ESR Builds
• Mozilla Foundation homepage
• Firefox Marketing/Advertising Site
• Template:Dmoz