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Firefox

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Mozilla Firefox is a free and open-source web browser. It is developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. A web browser is the primary software used to access and display information on the internet. Firefox is significant because it provides a flexible, community-driven alternative to commercial browsers.

Firefox 146.0.1 on Windows 11 screenshot
Firefox 146.0.1 on Windows 11 screenshot

It is available for many platforms, including Windows, macOS, and Linux. There are also mobile versions for Android and iOS.

Firefox 136 screenshot, macOS Sonoma
Firefox 136 screenshot, macOS Sonoma

To display web pages, Firefox relies on a specific mechanism called a rendering engine. Firefox uses the Gecko engine to implement current and anticipated web standards. This engine translates code into the visual layouts users see.

To handle interactive elements, it also uses the SpiderMonkey JavaScript engine. While desktop versions use Gecko, the iOS version must use the WebKit layout engine. This change is due to specific platform requirements on Apple devices. Firefox also implements various standards, such as HTML, XML, and SVG 1.1.

Acid3 Mozilla Firefox test
Acid3 Mozilla Firefox test

Firefox includes many specialized features for different types of users. For general browsing, it offers tabbed browsing, private browsing, and a download manager. It also features a screenshot tool and smart bookmarks. For web developers, Firefox provides an environment with built-in tools. These include the Error Console and the DOM Inspector.

Firefox for iOS 144 screenshot
Firefox for iOS 144 screenshot

Advanced users can access a configuration menu via "about:config" to change deep settings. The browser also supports Digital Rights Management, or DRM. This allows the playback of protected video content using modules like Google Widevine or Adobe Primetime. To keep this secure, these modules run in a "sandbox" environment to limit their access to the system.

Users can also expand the browser's capabilities through add-ons. These are extensions created by third-party developers using HTML, CSS, and JavaScript. They use an API known as WebExtensions, which is designed for compatibility with Chrome and Edge. Previously, Firefox used XUL and XPCOM APIs, which allowed add-ons to access internal browser functions. However, these were replaced to support a multi-process architecture.

Users can also apply different themes to change the visual appearance of the interface. These include light, dark, and system-specific themes.

The history of Firefox began with the Mozilla community, which was created by Netscape in 1998. In 2002, Dave Hyatt, Joe Hewitt, and Blake Ross started an experimental project. They wanted a standalone browser rather than the larger Mozilla Application Suite.

Phoenix 0.1
Phoenix 0.1

The project was originally codenamed "Phoenix," named after the mythical bird. In 2003, the name was changed to "Firebird" due to a trademark claim. After further pressure, it officially became Mozilla Firefox on February 9, 2004. The name "Firefox" is derived from a nickname for the red panda, which serves as the project's mascot.

Firefox mascot - FISL 16
Firefox mascot - FISL 16

Firefox saw rapid growth and significant milestones following its release. Version 1.0 launched on November 9, 2004. Within just nine months, the browser reached 60 million downloads. By November 2009, Firefox usage share peaked at 32.21 percent. During this time, Firefox 3.5 even overtook Internet Explorer 7 in usage.

StatCounter-browser-ww-yearly-2009-2025
StatCounter-browser-ww-yearly-2009-2025

However, its market share later declined as it faced competition from Google Chrome. In 2017, Mozilla introduced "Project Quantum" to modernize the browser. This update, found in Firefox 57, moved the browser to a multi-process model to improve performance.

Project Quantum changed how the browser handles tasks on a computer. Instead of using a single process, Firefox distributes tabs over four processes by default. This helps balance performance with memory consumption. If a page becomes unresponsive or crashes, it only affects the processes tied to that specific task. This architecture allows the browser to stay stable even when one part fails. This technical shift was considered the biggest update to the browser since version 1.0. It helped Firefox remain a competitive tool in the modern web ecosystem.

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🖼️ Images & Media (9)
File:Acid3 Mozilla Firefox test.png
Acid3 Mozilla Firefox test.png
File:Phoenix 0.1.png
Phoenix 0.1.png
Firefox 146.0.1 on Windows 11 screenshot.webp
File:Firefox 136 screenshot, macOS Sonoma.png
Firefox 136 screenshot, macOS Sonoma.png
Firefox 145.0 on Linux screenshot.webp
Firefox 136 on Fedora 41, browsing the...
File:Firefox for iOS 144 screenshot.png
Firefox for iOS 144 screenshot.png
File:Firefox mascot - FISL 16.jpg
Firefox mascot - FISL 16.jpg
File:StatCounter-browser-ww-yearly-2009-2025.png
StatCounter-browser-ww-yearly-2009-2025.png
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