List of Firefox features
has features which distinguish it from other web browsers, such as Google Chrome, Safari, and Microsoft Edge.
Major differences
To avoid interface bloat, ship a relatively smaller core customizable to meet individual users' needs, and allow for corporate or institutional extensions to meet their varying policies, Firefox relies on a robust extension system to allow users to modify the browser according to their requirements instead of providing all features in the standard distribution.While Opera and Google Chrome do the same, extensions for these are fewer in number as of late 2013. Internet Explorer also has an extension system but it is less widely supported than that of others. Developers supporting multiple browsers almost always support Firefox, and in many instances exclusively. As Opera has a policy of deliberately including more features in the core as they prove useful, the market for extensions is relatively unstable but also there is less need for them. The sheer number of extensions is not a good guide to the capabilities of a browser.
Protocol support and the difficulty of adding new link type protocols also vary widely across not only these browsers but across versions of these browsers. Opera has historically been most robust and consistent about supporting cutting-edge protocols such as robust file sharing eDonkey links or bitcoin transactions. These can be difficult to support in Firefox without relying on unknown small developers, which defeats the privacy purpose of these protocols. Instructions for supporting new link protocols vary widely across operating systems and Firefox versions, and are generally not implementable by end users who lack systems administration comfort and the ability to follow exact detailed instructions to type in strings.
Web technologies support
Firefox supports most basic Web standards including HTML, XML, XHTML, CSS, JavaScript, DOM, MathML, SVG, XSLT and XPath. Firefox's standards support and growing popularity have been credited as one reason Internet Explorer 7 was to be released with improved standards support.Since Web standards are often in contradiction with Internet Explorer's behaviors, Firefox, like other browsers, has a quirks mode. This mode attempts to mimic Internet Explorer's quirks modes, which equates to using obsolete rendering standards dating back to Internet Explorer 5, or alternately newer peculiarities introduced in IE 6 or 7. However, it is not completely compatible. Because of the differing rendering, PC World notes that a minority of pages do not work in Firefox, however Internet Explorer 7's quirks mode does not either.
CNET notes that Firefox does not support ActiveX controls by default, which can also cause webpages to be missing features or to not work at all in Firefox. Mozilla made the decision to not support ActiveX due to potential security vulnerabilities, its proprietary nature and its lack of cross-platform compatibility. There are methods of using ActiveX in Firefox such as via third-party plugins but they do not work in all versions of Firefox or on all platforms.
Beginning on December 8, 2006, Firefox Nightly builds pass the Acid2 CSS standards compliance test, so all future releases of Firefox 3 would pass the test.
Firefox also implements a proprietary protocol from Google called "safebrowsing", which is not an open standard.
Cross-platform support
Mozilla Firefox runs on certain platforms that coincide OS versions in use at the time of release. In 2004 version 1 supported older operating systems such as Windows 95 and Mac OS X 10.1, by 2008 version 3 required at least OS X 10.4 and even Windows 98 support ended.Various releases available on the primary distribution site can support the following operating systems, although not always the latest Firefox version.
- Various versions of Microsoft Windows, including 98, 98SE, ME, NT 4.0, 2000, XP, Server 2003, Vista, 7, 8 and 10.
- OS X
- Linux-based operating systems using X.Org Server or XFree86
Mozilla Firefox 1.x installation on Windows 95 requires .
Since Firefox is open source and Mozilla actively develops a platform independent abstraction for its graphical front end, it can also be compiled and run on a variety of other architectures and operating systems. Thus, Firefox is also available for many other systems. This includes OS/2, AIX, and FreeBSD. Builds for Windows XP Professional x64 Edition are also available. Mozilla Firefox is also the browser of choice for a good number of smaller operating systems, such as SkyOS and ZETA.
Firefox uses the same profile format on the different platforms, so a profile may be used on multiple platforms, if all of the platforms can access the same profile; this includes, for example, profiles stored on an NTFS or FAT32 partition accessible from both Windows and Linux, or on a USB flash drive. This is useful for users who dual-boot their machines. However, it may cause a few problems, especially with extensions.
Security
Firefox is free-libre software, and thus in particular its source code is visible to everyone. This allows anyone to review the code for security vulnerabilities. It also allowed the U.S. Department of Homeland Security to give funding for the automated tool Coverity to be run against Firefox code.Additionally, Mozilla has a security bug bounty system - anyone who reports a valid critical security bug receives a $3000 cash reward for each report and a Mozilla T-shirt. With effect from December 15, 2010, Mozilla added Web Applications to its Security Bug Bounty Program.
Tabbed browsing
Firefox supports tabbed browsing, which allows users to open several pages in one window. This feature was carried over from the Mozilla Application Suite, which in turn had borrowed the feature from the popular extension for Mozilla.Firefox also permits the "homepage" to be a list of URLs delimited with vertical bars, which are automatically opened in separate tabs, rather than a single page.
Firefox 2 supports more tabbed browsing features, including a "tab overflow" solution that keeps the user's tabs easily accessible when they would otherwise become illegible, a "session store" which lets the user keep the opened tabs across the restarts, and an "undo close tab" feature.
The tab browsing feature allows users to open multiple tabs or pages on one window. This is convenient for users who enjoy browsing from one window and is also advantageous in ensuring ease of browsing. The tabs are easily made accessible and users can close tabs that are not in use for better usability.
Pop-up blocking
Firefox also includes integrated customizable pop-up blocking. Firefox was given this feature early in beta development, and it was a major comparative selling point of the browser until Internet Explorer gained the capability in the Windows XP SP2 release of August 25, 2004. Firefox's pop-up blocking can be turned off entirely to allow pop-ups from all sites. Firefox's pop-up blocking can be inconvenient at times — it prevents JavaScript-based links from opening a new window while a page is loading unless the site is added to a "safe list" found in the options menu.In many cases, it is possible to view the pop-up's URL by clicking the dialog that appears when one is blocked. This makes it easier to decide if the pop-up should be displayed.
Private browsing
Private browsing was introduced in Firefox 3.5, which released on June 30, 2009. This feature lets users browse the Internet without leaving any traces in the browsing history.Download manager
An integrated customizable download manager is also included. Downloads can be opened automatically depending on the file type, or saved directly to a disk. By default, Firefox downloads all files to a user's desktop on Mac and Windows or to the user's home directory on Linux, but it can be configured to prompt for a specific download location. Version 3.0 added support for cross-session resuming. From within the download manager, a user can view the source URL from which a download originated as well as the location to which a file was downloaded.Live bookmarks
From 2004, live bookmarks allowed users to dynamically monitor changes to their favorite news sources, using RSS or Atom feeds. Instead of treating RSS-feeds as HTML pages as most news aggregators do, Firefox treated them as bookmarks and automatically updated them in real-time with a link to the appropriate source. In December 2018, version 64.0 of Firefox removed live bookmarks and web feeds, with Mozilla suggesting its replacement by add-ons or other software with news aggregator functionality like Mozilla Thunderbird.Other features
Find as you type
Firefox also has an incremental find feature known as "Find as you type", invoked by pressing Ctrl+F. With this feature enabled, a user can simply begin typing a word while viewing a web page, and Firefox automatically searches for it and highlights the first instance found. As the user types more of the word, Firefox refines its search. Also, if the user's exact query does not appear anywhere on the page, the "Find" box turns red. Ctrl+G can be pressed to go to the next found match.Alternatively the slash key can be used instead to invoke the "quick search". The "quick search", in contrast to the normal search, lacks search controls and is wholly controlled by the keyboard. In this mode highlighted links can be followed by pressing the enter key. The "quick search" has an alternate mode which is invoked by pressing the apostrophe key, in this mode only links are matched.