Difference between revisions of "Firefox"

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[[Category:Internet and Email (English)]]
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[[Category:Web browser]]
[[Category:HOWTOs (English)]]
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[[Category:Mozilla]]
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[[ar:Firefox]]
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[[cs:Firefox]]
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[[de:Firefox]]
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[[es:Firefox]]
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[[fr:Firefox]]
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[[it:Firefox]]
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[[ja:Firefox]]
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[[ko:Firefox]]
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[[ru:Firefox]]
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[[zh-hans:Firefox]]
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{{Related articles start}}
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{{Related|Browser plugins}}
 +
{{Related|Firefox/Tweaks}}
 +
{{Related|Firefox/Profile on RAM}}
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{{Related|Firefox/Privacy}}
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{{Related|Chromium}}
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{{Related|Opera}}
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{{Related articles end}}
 +
[https://www.mozilla.org/firefox Firefox] is a popular open source graphical web browser from [https://www.mozilla.org Mozilla].
  
Firefox is an open source web browser from [[Mozilla]]. The Firefox package in Archlinux is compiled without official branding. This means when you start Firefox it will use a blue globe for it's icon and will be named after it's release series' codename. This has to be done because a distribution may only use the trademarked and copy written parts of Firefox with permission from Mozilla.
+
== Installing ==
  
 +
Firefox can be [[install]]ed with the {{Pkg|firefox}} package.
  
= Enable Firefox Branding =
+
Other alternatives include:
If you would like to enable branding or simply change the user agent there are a  fews ways to do it. You can recompile, modify the browser with extensions, or use the advanced configuration.
 
== Recompile ==
 
We will use the [[ABS]] to rebuild Firefox. Make sure you have '''cvsup''' and '''wget''' installed. Now run
 
abs
 
If this is your first time running abs it may take awhile. Subsequent run will be much shorter. Before you make any custom package you should run abs. Now perform the following.
 
  
  mkdir /var/abs/local/firefox
+
* {{App|Firefox Developer Edition|for developers|https://www.mozilla.org/firefox/developer/|{{Pkg|firefox-developer-edition}}}}
  cp /var/abs/networking/firefox/* /var/abs/local/firefox
+
* {{App|Firefox Extended Support Release|long-term supported version|https://www.mozilla.org/firefox/organizations/|{{AUR|firefox-esr}} or {{AUR|firefox-esr-bin}}}}
  cd /var/abs/local/firefox
+
* {{App|Firefox Beta|cutting-edge version|https://www.mozilla.org/firefox/channel/desktop/#beta|{{AUR|firefox-beta}} or {{AUR|firefox-beta-bin}}}}
 +
* {{App|Firefox Nightly|nightly builds for testing ([https://developer.mozilla.org/Firefox/Experimental_features experimental features])|https://www.mozilla.org/firefox/channel/desktop/#nightly|{{AUR|firefox-nightly}}}}
 +
* {{App|Firefox KDE|Version of Firefox that incorporates an OpenSUSE patch for better [[#KDE/GNOME integration|KDE integration]] than is possible through simple Firefox plugins.|https://build.opensuse.org/package/show/mozilla:Factory/MozillaFirefox|{{AUR|firefox-kde-opensuse}}}}
 +
* On top of the different Mozilla build channels, a number of forks exist with more or less special features; see [[List of applications#Gecko-based]].
  
Now use your favorite editor and open the mozconfig file. Add the following line to the end of the file.
+
A number of language packs are available for Firefox, other than the standard English. Language packs are usually named as {{ic|firefox-i18n-''languagecode''}} (where {{ic|''languagecode''}} can be any language code, such as '''de''', '''ja''', '''fr''', etc.). For a list of available language packs see [https://www.archlinux.org/packages/extra/any/firefox-i18n/ firefox-i18n] for {{Pkg|firefox}},[https://www.archlinux.org/packages/community/any/firefox-developer-edition-i18n/ firefox-developer-edition-i18n] for {{Pkg|firefox-developer-edition}} and [https://aur.archlinux.org/packages/?K=firefox-nightly- firefox-nightly-] for {{AUR|firefox-nightly}}.
  
ac_add_options --enable-official-branding
+
== Add-ons ==
  
Save and exit, then run
+
Firefox is well known for its large library of add-ons which can be used to add new features or modify the behavior of existing features. Firefox's "Add-ons Manager" is used to manage installed add-ons or find new ones.
  
md5sum mozconfig
+
For instructions on how to install add-ons and a list of add-ons, see [[Browser extensions]].
  
Copy the string and then open the PKGBUILD file. Now look at the source and md5sums arrays. You can match up the md5sum to the file by comparing these two. In the most recent version of Firefox, Mozconfig is second on the sources list. So we would modify the second md5sum with the string we obtained earlier. The md5sum order is read from left to right. Now scroll down and look for these two lines, they will most likely be the last two lines.
+
=== Adding search engines ===
  
install -m644 ${startdir}/src/mozilla/browser/app/default.xpm ${startdir}/pkg/opt/mozilla/lib/firefox/chrome/icons/default/
+
Search engines can be added to Firefox through normal add-ons, see [https://addons.mozilla.org/firefox/search-tools/ this page] for a list of available search engines.
install -m644 ${startdir}/src/mozilla/browser/app/default.xpm ${startdir}/pkg/opt/mozilla/lib/firefox/icons/
 
  
Replace them with the following
+
A very extensive list of search engines can be found at the [https://mycroftproject.com/ Mycroft Project].
  
install -m644 ${startdir}/src/mozilla/dist/branding/default.xpm ${startdir}/pkg/opt/mozilla/lib/firefox/chrome/icons/default/
+
Also, you can use the [https://firefox.maltekraus.de/extensions/add-to-search-bar add-to-searchbar] extension to add a search to your search bar from any web site, by simply right clicking on the site's search field and selecting ''Add to Search Bar...''
install -m644 ${startdir}/src/mozilla/dist/branding/default.xpm ${startdir}/pkg/opt/mozilla/lib/firefox/icons/
 
  
Save and exit then run
+
==== arch-firefox-search ====
makepkg
 
This may take some time depending on your system. Once it has created the package remove your current version of Firefox if you have it installed.
 
pacman -Rd firefox
 
Then install the new version with
 
pacman -A firefox-*.pkg.tar.gz
 
You may also try upgrading your current Firefox with.
 
pacman -U firefox-*.pkg.tar.gz
 
  
Ofcourse replace * with your version number.
+
[[Install]] the {{AUR|arch-firefox-search}} package to add Arch-specific searches (AUR, wiki, forum, etc, as specified by user) to the Firefox search toolbar.
 
== Extensions ==
 
*[https://addons.mozilla.org/firefox/2553/ CCK Wizard] - Allows you to customize every aspect of Firefox. Title bar, user agent, icons, about graphic, and a lot more.  
 
  
*[https://addons.mozilla.org/firefox/59/ User Agent Switcher] - Adds a menu and a toolbar button to switch the user agent of the browser.
+
== Plugins ==
  
== Advanced Configuration ==
+
The only plugin supported by Firefox is [[Browser plugins#Adobe Flash Player|Adobe Flash Player]] (NPAPI version). Other plugins are [https://support.mozilla.org/en-US/kb/npapi-plugins no longer supported].
Enter <code>about:config</code> in your Firefox address bar to access the advanced configuration. In the filter enter <code>useragent.extra.firefox</code>, you will see your current user-agent string.You may put whatever you want in there. If you want to make it appear as the default version of Firefox to websites enter: <code>'''Firefox/2.0.0.1'''</code>
 
  
= Extensions =
+
To find out what plugins are installed/enabled, enter:
*[https://addons.mozilla.org/firefox/1865/ Adblock Plus] - Surprisingly it blocks ads.
 
*[https://addons.mozilla.org/firefox/446/ MediaPlayerConnectivity] - Allow you to launch embed video of website in an external application. Good for those who have problems with media plugins.
 
  
= Plugins =
+
about:plugins
To find out what extensions you have installed enter <code>about:plugins</code> in the Firefox address bar.
 
*Flash
 
pacman -S flashplugin
 
  
*Mplayer - Mplayer's multimedia plugin is one of the most mature. This will generally cover everything you need.
+
in the Firefox address bar or go to the ''Add-ons'' entry in the Firefox Menu and select the ''Plugins'' tab.
pacman -S mplayer-plugin
 
  
*Java
+
== Configuration ==
pacman -S jre
 
  
= Tips =
+
Firefox exposes a number of configuration options. To examine them, enter in the Firefox address bar:
== Fonts ==
 
===DPI===
 
Modifying the following value has been known to improve the way fonts looks in Firefox. Type about:config into your address bar. Type dpi into the filter, change '''layout.css.dpi''' to '''0'''.
 
===Font Replacement===
 
Another way to improve how fonts look is to replace them with another. Add or a create a ''.fonts.conf'' with the following.
 
  
  <match target="pattern">
+
  about:config
    <test qual="any" name="family"><string>tahoma</string></test>
 
    <edit name="family" mode="assign"><string>Bitstream Vera Sans</string></edit>
 
</match>
 
  
The first font name is the one we would like to replace. The second is the one we will be replacing it with.
+
Once set, these affect the user's current profile, and may be synchronized across all devices via [https://www.mozilla.org/firefox/sync/ Firefox Sync]. Please note that only a subset of the {{ic|about:config}} entries are synchronized by this method, and the exact subset may be found by searching for {{ic|services.sync.prefs}} in {{ic|about:config}}. Additional preferences and third party preferences may be synchronized by creating new boolean entries prepending the config value with {{ic|services.sync.prefs.sync}} ([https://developer.mozilla.org/en-US/docs/Archive/Mozilla/Firefox_Sync/Syncing_custom_preferences documentation] is still applicable.) To synchronize the whitelist for the extension [https://addons.mozilla.org/firefox/addon/noscript/ NoScript]:
=== Font Configuration ===
 
For more information on font configuration please read the following: [[XOrg Font Configuration]]
 
  
== Tip Articles==
+
services.sync.prefs.sync.capability.policy.maonoscript.sites
*[[Firefox Tips and Tweaks]]
 
*[[Adding Firefox Search Engines As User]]
 
  
= Firefox Derivatives =
+
The boolean {{ic|noscript.sync.enabled}} must be set to {{ic|true}} to synchronize the remainder of NoScript's preferences via Firefox Sync.
*[[Iceweasel]] - The name of two different Firefox forks. One is a GNU project based on Firefox 1.5. The other is being developed by Debian and it is based on 2.0. At the time of writing the [[AUR]] does have the GNU version of Iceweasel.
 
  
*[http://getswiftfox.com/ Swiftfox] - An optimized and processor specific build of Firefox. Currently available via AUR. It should be noted that considering Archlinux has ABS you could build your own optimized build of Firefox.
+
Firefox also allows configuration for a profile via a {{ic|user.js}} file: [http://kb.mozillazine.org/User.js_file user.js] kept in the profile folder, usually {{ic|~/.mozilla/firefox/''xxxxxxxx''.default/}}. For a useful starting point, see e.g [https://github.com/pyllyukko/user.js custom user.js] which is targeted at privacy/security conscious users.
  
= Firefox Alternatives =
+
One drawback of the above approach is that it is not applied system-wide. Furthermore, this is not useful as a "pre-configuration", since the profile directory is created after first launch of the browser. You can, however, let ''firefox'' create a new profile and, after closing it again, [https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles#w_restoring-a-profile-backup copy the contents] of an already created profile folder into it.  
*[[Opera]] - A very full featured web suite. Closed source but free (as in beer).
 
*[[Epiphany]] - Gnome's default web browser. Uses the same rendering engine as Firefox.
 
*[[Konqueror]] - KDE's default web browser. Uses the KHTML rending engine.
 
*[[Dillo]] - A very light weight browser.
 
*[[SeaMonkey]] - The continuation of the original Mozilla suite. Browser, email client, etc.  
 
  
= External Links =
+
Sometimes it may be desired to lock certain settings, a feature useful in widespread deployments of customized Firefox. In order to create a system-wide configuration, follow the steps outlined in [http://kb.mozillazine.org/Locking_preferences Locking preferences]:
*[http://www.howtocreate.co.uk/browserSpeed.html Browser Speed Comparisons] - Dated but still useful.
+
 
*[http://web.glandium.org/blog/?p=97 Facts about Debian and Mozilla® Firefox]-An account of the trademark issues from the Firefox package maintainer for Debian.
+
1. Create {{ic|/usr/lib/firefox/defaults/pref/local-settings.js}}:
*[http://www.gnu.org/software/gnuzilla/ Gnuzilla and IceWeasel] - Official website for the GNU Mozilla forks.
+
 
 +
pref("general.config.obscure_value", 0);
 +
pref("general.config.filename", "mozilla.cfg");
 +
 
 +
2. Create {{ic|/usr/lib/firefox/mozilla.cfg}} (this stores the actual configuration):
 +
 
 +
//
 +
//...your settings...
 +
// e.g to disable Pocket, uncomment the following line
 +
// lockPref("browser.pocket.enabled", false);
 +
 
 +
Please note that the first line must contain exactly {{ic|//}}. The syntax of the file is similar to that of {{ic|user.js}}.
 +
 
 +
=== Multimedia playback ===
 +
 
 +
Firefox uses [[FFmpeg]] for playing multimedia inside HTML5 {{ic|<audio>}} and {{ic|<video>}} elements. Go to [https://www.quirksmode.org/html5/tests/video.html video-test page] or [https://hpr.dogphilosophy.net/test/ audio-test page] to check which formats are actually supported.
 +
 
 +
HTML5 DRM playback is supported by the Google Widevine CDM, it is however not enabled by default. See ''Preferences > General > Digital Rights Management (DRM) Content'' if you want to learn more.
 +
 
 +
See [[Firefox/Tweaks#Enable additional media codecs]] for advanced configuration and enabling support for Widevine (Netflix, Amazon Video, etc.).
 +
 
 +
Firefox uses [[PulseAudio]] for audio playback and capture. For sound to work, you need to install the {{Pkg|pulseaudio}} package.
 +
 
 +
In case, for whatever reason, [[PulseAudio]] is not an option for you, you can use [[Advanced Linux Sound Architecture#PulseAudio compatibility|apulse]] instead. To make this work, it is necessary to exclude {{ic|/dev/snd/}} from Firefox' sandboxing by adding it to the comma-separated list in {{ic|about:config}}:
 +
 
 +
security.sandbox.content.write_path_whitelist
 +
 
 +
{{Note|The trailing slash on {{ic|/dev/snd/}} is important, otherwise ''apulse'' will report "Permission denied" errors.}}
 +
 
 +
If you have no audio even when using ''apulse'', try adding {{ic|16}} to {{ic|security.sandbox.content.syscall_whitelist}} in {{ic|about:config}}.
 +
 
 +
==== Open With extension ====
 +
 
 +
# Install [https://addons.mozilla.org/firefox/addon/open-with/ Open With] add-on.
 +
# Go to ''Add-ons > Open With > Preferences''.
 +
# Proceed with instructions to install a file in your system and test the installation.
 +
# Click ''Add browser''.
 +
# In the dialog write a name for this menu entry and command to start a video streaming capable player (e.g. [[mpv|/usr/bin/mpv]]).
 +
# (Optional step) Add needed arguments to the player (e.g. you may want {{ic|--force-window --ytdl}} for ''mpv'')
 +
# Right click on links or visit pages containing videos. Select newly created entry from Open With's menu and if the site is supported, the player will open as expected.
 +
 
 +
The same procedure can be used to associate video downloaders such as ''youtube-dl''.
 +
 
 +
=== Spell checking ===
 +
 
 +
Firefox can use system-wide installed [[Hunspell]] dictionaries as well as dictionaries installed through its own extension system.
 +
 
 +
To enable spell checking for a specific language right click on any text field and check the ''Check Spelling'' box. To select a language for spell checking to you have right click again and select your language from the ''Languages'' sub-menu.
 +
 
 +
When your default language choice does not stick, see [[#Firefox does not remember default spell check language]].
 +
 
 +
==== System-wide Hunspell dictionaries ====
 +
 
 +
Install [[Hunspell]] and its dictionaries for the languages you require.
 +
 
 +
==== Dictionaries as extensions ====
 +
 
 +
To get more languages right click on any text field and just click ''Add Dictionaries...'' and select the dictionary you want to install from the [https://addons.mozilla.org/firefox/language-tools/ Dictionaries and Language Packs list].
 +
 
 +
{{Tip|For Russian, the extension is packaged as {{Pkg|firefox-spell-ru}}.}}
 +
 
 +
=== KDE/GNOME integration ===
 +
 
 +
* To bring the [[KDE]] look to GTK apps (including Firefox), install {{Pkg|breeze-gtk}} and {{Pkg|kde-gtk-config}}. Afterwards, go to ''System Settings > Application Style > GNOME/GTK Application Style''. Be sure to choose 'Breeze' in 'Select a GTK2/GTK3 Theme' and check 'Show icons in GTK buttons' and 'Show icons in GTK menus'.
 +
* To make the left mouse button warp the scrollbar instead of the middle one on KDE, go to ''System Settings > Application Style > GNOME/GTK Application Style'' and choose 'Jump to the mouse cursor position' in the 'On left-clicking the scroll bar' option.
 +
* To use the KDE file selection and print dialogs in Firefox 64 or newer:
 +
*# Install {{Pkg|xdg-desktop-portal}} and {{Pkg|xdg-desktop-portal-kde}},
 +
*# Set {{ic|1=GTK_USE_PORTAL=1}} as [[environment variable]] or  [[Desktop entries#Modify environment variables|edit the .desktop file]] and add {{ic|1=GTK_USE_PORTAL=1}} to the {{ic|Exec}} lines.
 +
* For integration with [[KDE]] MIME type system and file dialog, one can use {{AUR|firefox-kde-opensuse}} variant from AUR with OpenSUSE’s patches applied. Alternatively, integration with MIME types can be achieved by creating a symbolic link to the MIME database {{ic|~/.config/mimeapps.list}} from the deprecated {{ic|~/.local/share/applications/mimeapps.list}} that is used by Firefox. See [[XDG MIME Applications#mimeapps.list]].
 +
* Extensions/add-ons may provide additional integration, such as:
 +
** Browser integration in [[Plasma]]: requires {{Pkg|plasma-browser-integration}} and the [https://addons.mozilla.org/firefox/addon/plasma-integration/ Plasma Integration add-on].
 +
** {{AUR|mozilla-extension-gnome-keyring-git}} (all-JavaScript implementation) to integrate Firefox with [[GNOME Keyring]]. To make firefox-gnome-keyring use your login keychain, set {{ic|extensions.gnome-keyring.keyringName}} to {{ic|login}} in {{ic|about:config}}. Note the lowercase 'l' despite the the keychain name having an uppercase 'L' in Seahorse.
 +
 
 +
=== Smooth Scrolling ===
 +
 
 +
{{Merge|Firefox/Tweaks#Mouse and keyboard|Keep similar things in one place.}}
 +
 
 +
In order to get smooth physics-based scrolling in Firefox, the {{ic|general.smoothScroll.msdPhysics}} configurations can be changed to emulate a snappier behaviour like in other web browsers. For a quicker configuration, append the following to {{ic|~/.mozilla/firefox/'''your-profile'''/user.js}} (requires restart):
 +
 
 +
user_pref("general.smoothScroll.lines.durationMaxMS", 125);
 +
user_pref("general.smoothScroll.lines.durationMinMS", 125);
 +
user_pref("general.smoothScroll.mouseWheel.durationMaxMS", 200);
 +
user_pref("general.smoothScroll.mouseWheel.durationMinMS", 100);
 +
user_pref("general.smoothScroll.msdPhysics.enabled", true);
 +
user_pref("general.smoothScroll.other.durationMaxMS", 125);
 +
user_pref("general.smoothScroll.other.durationMinMS", 125);
 +
user_pref("general.smoothScroll.pages.durationMaxMS", 125);
 +
user_pref("general.smoothScroll.pages.durationMinMS", 125);
 +
 
 +
Additionally the mouse wheel scroll settings have to be changed to react in a smooth way as well:
 +
 
 +
user_pref("mousewheel.min_line_scroll_amount", 30);
 +
user_pref("mousewheel.system_scroll_override_on_root_content.enabled", true);
 +
user_pref("mousewheel.system_scroll_override_on_root_content.horizontal.factor", 175);
 +
user_pref("mousewheel.system_scroll_override_on_root_content.vertical.factor", 175);
 +
user_pref("toolkit.scrollbox.horizontalScrollDistance", 6);
 +
user_pref("toolkit.scrollbox.verticalScrollDistance", 2);
 +
 
 +
If you have troubles on machines with varying performance, try modifying the {{ic|mousewheel.min_line_scroll_amount}} until it feels snappy enough.
 +
 
 +
== Tips and tricks ==
 +
 
 +
For general enhancements see [[Firefox/Tweaks]], for privacy related enhancements see [[Firefox/Privacy]].
 +
 
 +
=== Dark themes ===
 +
 
 +
If a dark [[GTK]] theme is in use (e.g. Arc Dark), it is recommended to start Firefox with a brighter one (e.g. Adwaita). See [[GTK#Themes]] and [[Firefox/Tweaks#Unreadable input fields with dark GTK themes]] for more information.
 +
 
 +
Alternatively, starting with Firefox 68 you can make the all Firefox interfaces and even other websites respect dark themes, irrespective of the system GTK theme and Firefox theme. To do this, set {{ic|browser.in-content.dark-mode}} to {{ic|true}} and {{ic|ui.systemUsesDarkTheme}} to {{ic|1}} in {{ic|about:config}} [https://bugzilla.mozilla.org/show_bug.cgi?id=1488384#c23].
 +
 
 +
=== Frame rate ===
 +
 
 +
If Firefox is unable to automatically detect the right value, it will default to 60 fps. To manually correct this, set {{ic|layout.frame_rate}} to the refresh rate of your monitor (e.g. 144 for 144 Hz).
 +
 
 +
=== Memory limit ===
 +
 
 +
To prevent pages from abusing memory (and possible [[Wikipedia:Out_of_memory|OOM]]), we can use [[Firejail]] with the {{ic|rlimit-as}} option.
 +
 
 +
=== New tabs position ===
 +
 
 +
To control where new tabs appears (relative or absolute), use {{ic|browser.tabs.insertAfterCurrent}} and {{ic|browser.tabs.insertRelatedAfterCurrent}}. See [https://support.mozilla.org/en/questions/1229062] for more informations.
 +
 
 +
=== Screenshot of webpage ===
 +
 
 +
You can ''Take a Screenshot'' by either clicking the ''Page actions'' button (the three horizontal dots) in the address bar or by right-clicking on the webpage. See [https://support.mozilla.org/en-US/kb/firefox-screenshots] for more information.
 +
 
 +
As an alternative you can use the screenshot button in the [https://developer.mozilla.org/en-US/docs/Tools/Taking_screenshots Developer Tools].
 +
 
 +
=== Wayland ===
 +
 
 +
More recent versions of Firefox support opting into Wayland via an environment variable.
 +
 
 +
$ MOZ_ENABLE_WAYLAND=1 firefox
 +
 
 +
You may enter {{ic|about:support}} in the URL bar to check the ''Window Protocol''. It should say ''wayland'' instead of ''x11''.
 +
 
 +
To make this permanent, see [[Environment variables#Graphical environment]] and start Firefox via the desktop launcher like you normally would. To verify it worked check the ''Window Protocol'' again.
 +
 
 +
=== Window manager rules ===
 +
 
 +
To apply different configurations to Firefox windows, change the WM_CLASS string by using Firefox's {{ic|--class}} option, to a custom one.
 +
 
 +
==== Profiles ====
 +
 
 +
To start new Firefox instances, multiple profiles are required. To create a new profile:
 +
 
 +
$ firefox [--new-instance] -P
 +
 
 +
Class can be specified when launching Firefox with a not-in-use profile:
 +
 
 +
$ firefox [--new-instance] -P ''profile_name'' --class=''class_name''
 +
 
 +
=== Touchscreen gestures and pixel-perfect trackpad scrolling ===
 +
 
 +
{{Merge|Firefox/Tweaks#Enable touchscreen gestures|Same solution.}}
 +
 
 +
To enable touch gestures (like scrolling and pinch-to-zoom) and one-to-one trackpad scrolling (as can be witnessed with GTK3 applications like Nautilus), set the {{ic|1=MOZ_USE_XINPUT2=1}} [[environment variable]] before starting Firefox.
 +
 
 +
== Troubleshooting ==
 +
 
 +
=== All Firefox extensions disabled (May 2019) ===
 +
 
 +
{{Warning|'''Do not''' delete and re-install your addons to try and fix the issue, as you will lose your addons' data.}}
 +
 
 +
Between 3–5 May 2019, all Firefox addons (web extensions, themes, search engines, and language packs) were mistakenly marked as '''Legacy addons''', and could not be enabled. The [https://bugzilla.mozilla.org/show_bug.cgi?id=1548973 bug] was caused by an expired intermediate certificate.
 +
 
 +
For most users, the issue has been fixed in Firefox 66.0.4 and Firefox ESR 60.6.2. The addons should be automatically re-enabled as soon as the patched version of Firefox is installed. Certain users, such as those who have set a Master Password, might require extra steps. Please see Firefox's [https://support.mozilla.org/en-US/kb/add-ons-disabled-or-fail-to-install-firefox official support page] for more information.
 +
 
 +
=== Firefox startup takes very long ===
 +
 
 +
If Firefox takes much longer to start up than other browsers, it may be due to lacking configuration of the localhost in  {{ic|/etc/hosts}}. See [[Network configuration#Local network hostname resolution]] on how to set it up.
 +
 
 +
=== Font troubleshooting ===
 +
 
 +
See [[Font configuration]].
 +
 
 +
Firefox has a setting which determines how many replacements it will allow from fontconfig. To allow it to use all your replacement-rules, change {{ic|gfx.font_rendering.fontconfig.max_generic_substitutions}} to {{ic|127}} (the highest possible value).
 +
 
 +
=== Setting an email client ===
 +
 
 +
Inside the browser, {{ic|mailto}} links by default are opened by a web application such as Gmail or Yahoo Mail. To set an external email program, go to ''Preferences > Applications'' and modify the ''action'' corresponding to the {{ic|mailto}} content type; the file path will need to be designated (e.g. {{ic|/usr/bin/kmail}} for Kmail).
 +
 
 +
Outside the browser, {{ic|mailto}} links are handled by the {{ic|x-scheme-handler/mailto}} mime type, which can be easily configured with [[xdg-mime]]. See [[Default applications]] for details and alternatives.
 +
 
 +
=== File association ===
 +
 
 +
See [[Default applications]].
 +
 
 +
=== Firefox keeps creating ~/Desktop even when this is not desired ===
 +
 
 +
Firefox uses {{ic|~/Desktop}} as the default place for download and upload files. To change it to another folder, set the {{ic|XDG_DESKTOP_DIR}} option as explained in [[XDG user directories]].
 +
 
 +
=== Make plugins respect blocked pop-ups ===
 +
 
 +
Some plugins can misbehave and bypass the default settings, such as the Flash plugin. You can prevent this by doing the following:
 +
 
 +
# Type {{ic|about:config}} into the address bar.
 +
# Right-click on the page and select ''New > Integer''.
 +
# Name it {{ic|privacy.popups.disable_from_plugins}}.
 +
# Set the value to {{ic|2}}.
 +
 
 +
The possible values are:
 +
 
 +
* {{ic|'''0'''}}: Allow all popups from plugins.
 +
* {{ic|'''1'''}}: Allow popups, but limit them to {{ic|dom.popup_maximum}}.
 +
* {{ic|'''2'''}}: Block popups from plugins.
 +
* {{ic|'''3'''}}: Block popups from plugins, even on whitelisted sites.
 +
 
 +
=== Middle-click behavior ===
 +
 
 +
To use the middle mouse button to paste whatever text has been highlighted/added to the clipboard, as is common in UNIX-like operating systems, set either {{ic|middlemouse.contentLoadURL}} or {{ic|middlemouse.paste}} to {{ic|true}} in {{ic|about:config}}. Having {{ic|middlemouse.contentLoadURL}} enabled was the default behaviour prior to Firefox 57.
 +
 
 +
To scroll on middle-click (default for Windows browsers) set {{ic|general.autoScroll}} to {{ic|true}}.
 +
 
 +
=== Backspace does not work as the 'Back' button ===
 +
 
 +
According to [http://kb.mozillazine.org/Browser.backspace_action MozillaZine], the {{ic|Backspace}} key was mapped based on which platform the browser was running on. As a compromise, this preference was created to allow the {{ic|Backspace}} key to either go back/forward, scroll up/down a page, or do nothing.
 +
 
 +
To make {{ic|Backspace}} go back one page in the tab's history and {{ic|Shift+Backspace}} go forward, set {{ic|browser.backspace_action}} to {{ic|0}} in {{ic|about:config}}.
 +
 
 +
To have the {{ic|Backspace}} key scroll up one page and {{ic|Shift+Backspace}} scroll down one page, set {{ic|browser.backspace_action}} to {{ic|1}}. Setting this property to any other value will leave the key unmapped (Arch Linux defaults to {{ic|2}}, in other words, it is unmapped by default).
 +
 
 +
=== Firefox does not remember login information ===
 +
 
 +
It may be due to a corrupted {{ic|cookies.sqlite}} file in [https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data Firefox's profile] folder. In order to fix this, just rename or remove {{ic|cookie.sqlite}} while Firefox is not running.
 +
 
 +
Open a terminal of choice and type the following:
 +
 
 +
$ rm -f ~/.mozilla/firefox/<profile id>.default/cookies.sqlite
 +
 
 +
The profile id is a random 8 character string.
 +
 
 +
Restart Firefox and see if it solved the problem.
 +
 
 +
=== Cannot enter/leave fullscreen ===
 +
 
 +
If Firefox detects an [https://specifications.freedesktop.org/wm-spec/wm-spec-latest.html EWMH/ICCCM] compliant window manager, it will try to send a WM_STATE message to the root window to request Firefox be made to enter (or leave) full-screen mode (as defined by the window manager). Window managers are allowed to ignore it, but if they do, Firefox will assume the request got denied and propagate it to the end user which results in nothing happening. This may result in not being able to full screen a video. A general workaround is to set the {{ic|full-screen-api.ignore-widgets}} to {{ic|true}} in {{ic|about:config}}. 
 +
 
 +
Related bug reports: [https://bugzilla.mozilla.org/show_bug.cgi?id=1189622 Bugzilla 1189622].
 +
 
 +
=== "Do you want Firefox to save your tabs for the next time it starts?" dialog does not appear ===
 +
 
 +
From the [https://support.mozilla.com/en-US/questions/767751 Mozilla support] site:
 +
 
 +
# Type {{ic|about:config}} in the address bar.
 +
# Set {{ic|browser.warnOnQuit}} to {{ic|true}}.
 +
# Set {{ic|browser.showQuitWarning}} to {{ic|true}}.
 +
 
 +
=== Firefox detects the wrong version of my plugin ===
 +
 
 +
When you close Firefox, the latter saves the current timestamp and version of your plugins inside {{ic|pluginreg.dat}} located in your profile folder, typically in {{ic|~/.mozilla/firefox/''xxxxxxxx''.default/}}.
 +
 
 +
If you upgraded your plugin when Firefox was still running, you will thus have the wrong information inside that file. The next time you will restart Firefox you will get that message {{ic|Firefox has prevented the outdated plugin "XXXX" from running on ...}} when you will be trying to open content dedicated to that plugin on the web. This problem often appears with the official [[Browser plugins#Adobe Flash Player|Adobe Flash Player plugin]] which has been upgraded while Firefox was still running.
 +
 
 +
The solution is to remove the file {{ic|pluginreg.dat}} from your profile and that is it. Firefox will not complain about the missing file as it will be recreated the next time Firefox will be closed. [https://bugzilla.mozilla.org/show_bug.cgi?id=1109795#c16]
 +
 
 +
=== JavaScript context menu does not appear on some sites ===
 +
 
 +
You can try setting {{ic|dom.w3c_touch_events.enabled}} to {{ic|0}} in {{ic|about:config}}.
 +
 
 +
=== Firefox does not remember default spell check language ===
 +
 
 +
The default spell checking language can be set as follows:
 +
 
 +
# Type {{ic|about:config}} in the address bar.
 +
# Set {{ic|spellchecker.dictionary}} to your language of choice, for instance {{ic|en_GB}}.
 +
# Notice that the for dictionaries installed as a Firefox plugin the notation is {{ic|en-GB}}, and for {{Pkg|hunspell}} dictionaries the notation is {{ic|en_GB}}.
 +
 
 +
When you only have system wide dictionaries installed with {{Pkg|hunspell}}, Firefox might not remember your default dictionary language settings. This can be fixed by having at least one [https://addons.mozilla.org/firefox/language-tools/ dictionary] installed as a Firefox plugin. Notice that now you will also have a tab ''Dictionaries'' in ''Add-ons''. You may have to change the order of ''preferred language for displaying pages'' in {{ic|about:preferences#general}} to make the spell check default to the language of the addon dictionary.
 +
 
 +
Related questions on the '''StackExchange''' platform: [https://stackoverflow.com/questions/26936792/change-firefox-spell-check-default-language/29446115], [https://stackoverflow.com/questions/21542515/change-default-language-on-firefox/29446353], [https://askubuntu.com/questions/184300/how-can-i-change-firefoxs-default-dictionary/576877]
 +
 
 +
Related bug reports: [https://bugzilla.mozilla.org/show_bug.cgi?id=776028 Bugzilla 776028], [https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1026869 Ubuntu bug 1026869]
 +
 
 +
=== Some MathML symbols are missing ===
 +
 
 +
You need some Math fonts, namely Latin Modern Math and STIX (see this MDN page: [https://developer.mozilla.org/en-US/docs/Mozilla/MathML_Project/Fonts#Linux]), to display MathML correctly.
 +
 
 +
In Arch Linux, these fonts are provided by {{Pkg|texlive-core}} '''and''' {{Pkg|texlive-fontsextra}}, but they are not available to fontconfig by default. See [[TeX Live#Making fonts available to Fontconfig]] for details. You can also try other [[Fonts#Math|Math fonts]].
 +
 
 +
=== Tearing video in fullscreen mode ===
 +
 
 +
If you are using the Xorg Intel or Nouveau drivers and experience tearing video in fullscreen mode, try [[Firefox tweaks#Enable OpenGL Off-Main-Thread Compositing (OMTC)]].
 +
 
 +
=== Tearing when scrolling ===
 +
 
 +
Try disabling smooth scrolling in ''Preferences > Browsing''.
 +
 
 +
=== Firefox WebRTC module cannot detect a microphone ===
 +
 
 +
WebRTC applications for instance [https://mozilla.github.io/webrtc-landing/gum_test.html Firefox WebRTC getUserMedia test page] say that microphone cannot be found. Issue is reproducible for both ALSA or PulseAudio setup. Firefox debug logs show the following error:
 +
 
 +
{{hc|1=$ NSPR_LOG_MODULES=MediaManager:5,GetUserMedia:5 firefox|2=
 +
...
 +
[Unnamed thread 0x7fd7c0654340]: D/GetUserMedia  VoEHardware:GetRecordingDeviceName: Failed 1
 +
}}
 +
 
 +
You can try setting {{ic|media.navigator.audio.full_duplex}} property to {{ic|false}} at {{ic|about:config}} Firefox page and restart Firefox.
 +
 
 +
This can also help if you are using the PulseAudio [[PulseAudio/Troubleshooting#Enable Echo/Noise-Cancellation|module-echo-cancel]] and Firefox does not recognise the virtual echo canceling source.
 +
 
 +
=== Cannot login with my Chinese account ===
 +
 
 +
Firefox provides a local service for Chinese users, with a local account totally different from the international one. Firefox installed with the {{Pkg|firefox}} package uses the international account system by default, to change into the Chinese local service, you should install the add-on manager on [http://mozilla.com.cn/thread-343905-1-1.html this page], then you can login with your Chinese account now.
 +
 
 +
== See also ==
 +
 
 +
* [https://www.mozilla.org/firefox/ Official website]
 +
* [https://www.mozilla.org/ Mozilla Foundation]
 +
* [[MozillaWiki:Firefox]]
 +
* [https://addons.mozilla.org/ Firefox Add-ons]
 +
* [https://addons.mozilla.org/firefox/themes/ Firefox themes]
 +
* [[Wikipedia:Mozilla Firefox]]
 +
* [http://forums.mozillazine.org/ mozillaZine] unofficial forums

Latest revision as of 10:33, 11 December 2019

Firefox is a popular open source graphical web browser from Mozilla.

Installing

Firefox can be installed with the firefox package.

Other alternatives include:

  • Firefox Developer Edition — for developers
https://www.mozilla.org/firefox/developer/ || firefox-developer-edition
  • Firefox Extended Support Release — long-term supported version
https://www.mozilla.org/firefox/organizations/ || firefox-esrAUR or firefox-esr-binAUR
  • Firefox Beta — cutting-edge version
https://www.mozilla.org/firefox/channel/desktop/#beta || firefox-betaAUR or firefox-beta-binAUR
https://www.mozilla.org/firefox/channel/desktop/#nightly || firefox-nightlyAUR
  • Firefox KDE — Version of Firefox that incorporates an OpenSUSE patch for better KDE integration than is possible through simple Firefox plugins.
https://build.opensuse.org/package/show/mozilla:Factory/MozillaFirefox || firefox-kde-opensuseAUR

A number of language packs are available for Firefox, other than the standard English. Language packs are usually named as firefox-i18n-languagecode (where languagecode can be any language code, such as de, ja, fr, etc.). For a list of available language packs see firefox-i18n for firefox,firefox-developer-edition-i18n for firefox-developer-edition and firefox-nightly- for firefox-nightlyAUR.

Add-ons

Firefox is well known for its large library of add-ons which can be used to add new features or modify the behavior of existing features. Firefox's "Add-ons Manager" is used to manage installed add-ons or find new ones.

For instructions on how to install add-ons and a list of add-ons, see Browser extensions.

Adding search engines

Search engines can be added to Firefox through normal add-ons, see this page for a list of available search engines.

A very extensive list of search engines can be found at the Mycroft Project.

Also, you can use the add-to-searchbar extension to add a search to your search bar from any web site, by simply right clicking on the site's search field and selecting Add to Search Bar...

arch-firefox-search

Install the arch-firefox-searchAUR package to add Arch-specific searches (AUR, wiki, forum, etc, as specified by user) to the Firefox search toolbar.

Plugins

The only plugin supported by Firefox is Adobe Flash Player (NPAPI version). Other plugins are no longer supported.

To find out what plugins are installed/enabled, enter:

about:plugins

in the Firefox address bar or go to the Add-ons entry in the Firefox Menu and select the Plugins tab.

Configuration

Firefox exposes a number of configuration options. To examine them, enter in the Firefox address bar:

about:config

Once set, these affect the user's current profile, and may be synchronized across all devices via Firefox Sync. Please note that only a subset of the about:config entries are synchronized by this method, and the exact subset may be found by searching for services.sync.prefs in about:config. Additional preferences and third party preferences may be synchronized by creating new boolean entries prepending the config value with services.sync.prefs.sync (documentation is still applicable.) To synchronize the whitelist for the extension NoScript:

services.sync.prefs.sync.capability.policy.maonoscript.sites

The boolean noscript.sync.enabled must be set to true to synchronize the remainder of NoScript's preferences via Firefox Sync.

Firefox also allows configuration for a profile via a user.js file: user.js kept in the profile folder, usually ~/.mozilla/firefox/xxxxxxxx.default/. For a useful starting point, see e.g custom user.js which is targeted at privacy/security conscious users.

One drawback of the above approach is that it is not applied system-wide. Furthermore, this is not useful as a "pre-configuration", since the profile directory is created after first launch of the browser. You can, however, let firefox create a new profile and, after closing it again, copy the contents of an already created profile folder into it.

Sometimes it may be desired to lock certain settings, a feature useful in widespread deployments of customized Firefox. In order to create a system-wide configuration, follow the steps outlined in Locking preferences:

1. Create /usr/lib/firefox/defaults/pref/local-settings.js:

pref("general.config.obscure_value", 0);
pref("general.config.filename", "mozilla.cfg");

2. Create /usr/lib/firefox/mozilla.cfg (this stores the actual configuration):

//
//...your settings...
// e.g to disable Pocket, uncomment the following line
// lockPref("browser.pocket.enabled", false);

Please note that the first line must contain exactly //. The syntax of the file is similar to that of user.js.

Multimedia playback

Firefox uses FFmpeg for playing multimedia inside HTML5 <audio> and <video> elements. Go to video-test page or audio-test page to check which formats are actually supported.

HTML5 DRM playback is supported by the Google Widevine CDM, it is however not enabled by default. See Preferences > General > Digital Rights Management (DRM) Content if you want to learn more.

See Firefox/Tweaks#Enable additional media codecs for advanced configuration and enabling support for Widevine (Netflix, Amazon Video, etc.).

Firefox uses PulseAudio for audio playback and capture. For sound to work, you need to install the pulseaudio package.

In case, for whatever reason, PulseAudio is not an option for you, you can use apulse instead. To make this work, it is necessary to exclude /dev/snd/ from Firefox' sandboxing by adding it to the comma-separated list in about:config:

security.sandbox.content.write_path_whitelist
Note: The trailing slash on /dev/snd/ is important, otherwise apulse will report "Permission denied" errors.

If you have no audio even when using apulse, try adding 16 to security.sandbox.content.syscall_whitelist in about:config.

Open With extension

  1. Install Open With add-on.
  2. Go to Add-ons > Open With > Preferences.
  3. Proceed with instructions to install a file in your system and test the installation.
  4. Click Add browser.
  5. In the dialog write a name for this menu entry and command to start a video streaming capable player (e.g. /usr/bin/mpv).
  6. (Optional step) Add needed arguments to the player (e.g. you may want --force-window --ytdl for mpv)
  7. Right click on links or visit pages containing videos. Select newly created entry from Open With's menu and if the site is supported, the player will open as expected.

The same procedure can be used to associate video downloaders such as youtube-dl.

Spell checking

Firefox can use system-wide installed Hunspell dictionaries as well as dictionaries installed through its own extension system.

To enable spell checking for a specific language right click on any text field and check the Check Spelling box. To select a language for spell checking to you have right click again and select your language from the Languages sub-menu.

When your default language choice does not stick, see #Firefox does not remember default spell check language.

System-wide Hunspell dictionaries

Install Hunspell and its dictionaries for the languages you require.

Dictionaries as extensions

To get more languages right click on any text field and just click Add Dictionaries... and select the dictionary you want to install from the Dictionaries and Language Packs list.

Tip: For Russian, the extension is packaged as firefox-spell-ru.

KDE/GNOME integration

  • To bring the KDE look to GTK apps (including Firefox), install breeze-gtk and kde-gtk-config. Afterwards, go to System Settings > Application Style > GNOME/GTK Application Style. Be sure to choose 'Breeze' in 'Select a GTK2/GTK3 Theme' and check 'Show icons in GTK buttons' and 'Show icons in GTK menus'.
  • To make the left mouse button warp the scrollbar instead of the middle one on KDE, go to System Settings > Application Style > GNOME/GTK Application Style and choose 'Jump to the mouse cursor position' in the 'On left-clicking the scroll bar' option.
  • To use the KDE file selection and print dialogs in Firefox 64 or newer:
    1. Install xdg-desktop-portal and xdg-desktop-portal-kde,
    2. Set GTK_USE_PORTAL=1 as environment variable or edit the .desktop file and add GTK_USE_PORTAL=1 to the Exec lines.
  • For integration with KDE MIME type system and file dialog, one can use firefox-kde-opensuseAUR variant from AUR with OpenSUSE’s patches applied. Alternatively, integration with MIME types can be achieved by creating a symbolic link to the MIME database ~/.config/mimeapps.list from the deprecated ~/.local/share/applications/mimeapps.list that is used by Firefox. See XDG MIME Applications#mimeapps.list.
  • Extensions/add-ons may provide additional integration, such as:

Smooth Scrolling

Merge-arrows-2.pngThis article or section is a candidate for merging with Firefox/Tweaks#Mouse and keyboard.Merge-arrows-2.png

Notes: Keep similar things in one place. (Discuss in Talk:Firefox#)

In order to get smooth physics-based scrolling in Firefox, the general.smoothScroll.msdPhysics configurations can be changed to emulate a snappier behaviour like in other web browsers. For a quicker configuration, append the following to ~/.mozilla/firefox/your-profile/user.js (requires restart):

user_pref("general.smoothScroll.lines.durationMaxMS", 125);
user_pref("general.smoothScroll.lines.durationMinMS", 125);
user_pref("general.smoothScroll.mouseWheel.durationMaxMS", 200);
user_pref("general.smoothScroll.mouseWheel.durationMinMS", 100);
user_pref("general.smoothScroll.msdPhysics.enabled", true);
user_pref("general.smoothScroll.other.durationMaxMS", 125);
user_pref("general.smoothScroll.other.durationMinMS", 125);
user_pref("general.smoothScroll.pages.durationMaxMS", 125);
user_pref("general.smoothScroll.pages.durationMinMS", 125);

Additionally the mouse wheel scroll settings have to be changed to react in a smooth way as well:

user_pref("mousewheel.min_line_scroll_amount", 30);
user_pref("mousewheel.system_scroll_override_on_root_content.enabled", true);
user_pref("mousewheel.system_scroll_override_on_root_content.horizontal.factor", 175);
user_pref("mousewheel.system_scroll_override_on_root_content.vertical.factor", 175);
user_pref("toolkit.scrollbox.horizontalScrollDistance", 6);
user_pref("toolkit.scrollbox.verticalScrollDistance", 2);

If you have troubles on machines with varying performance, try modifying the mousewheel.min_line_scroll_amount until it feels snappy enough.

Tips and tricks

For general enhancements see Firefox/Tweaks, for privacy related enhancements see Firefox/Privacy.

Dark themes

If a dark GTK theme is in use (e.g. Arc Dark), it is recommended to start Firefox with a brighter one (e.g. Adwaita). See GTK#Themes and Firefox/Tweaks#Unreadable input fields with dark GTK themes for more information.

Alternatively, starting with Firefox 68 you can make the all Firefox interfaces and even other websites respect dark themes, irrespective of the system GTK theme and Firefox theme. To do this, set browser.in-content.dark-mode to true and ui.systemUsesDarkTheme to 1 in about:config [1].

Frame rate

If Firefox is unable to automatically detect the right value, it will default to 60 fps. To manually correct this, set layout.frame_rate to the refresh rate of your monitor (e.g. 144 for 144 Hz).

Memory limit

To prevent pages from abusing memory (and possible OOM), we can use Firejail with the rlimit-as option.

New tabs position

To control where new tabs appears (relative or absolute), use browser.tabs.insertAfterCurrent and browser.tabs.insertRelatedAfterCurrent. See [2] for more informations.

Screenshot of webpage

You can Take a Screenshot by either clicking the Page actions button (the three horizontal dots) in the address bar or by right-clicking on the webpage. See [3] for more information.

As an alternative you can use the screenshot button in the Developer Tools.

Wayland

More recent versions of Firefox support opting into Wayland via an environment variable.

$ MOZ_ENABLE_WAYLAND=1 firefox

You may enter about:support in the URL bar to check the Window Protocol. It should say wayland instead of x11.

To make this permanent, see Environment variables#Graphical environment and start Firefox via the desktop launcher like you normally would. To verify it worked check the Window Protocol again.

Window manager rules

To apply different configurations to Firefox windows, change the WM_CLASS string by using Firefox's --class option, to a custom one.

Profiles

To start new Firefox instances, multiple profiles are required. To create a new profile:

$ firefox [--new-instance] -P

Class can be specified when launching Firefox with a not-in-use profile:

$ firefox [--new-instance] -P profile_name --class=class_name

Touchscreen gestures and pixel-perfect trackpad scrolling

Merge-arrows-2.pngThis article or section is a candidate for merging with Firefox/Tweaks#Enable touchscreen gestures.Merge-arrows-2.png

Notes: Same solution. (Discuss in Talk:Firefox#)

To enable touch gestures (like scrolling and pinch-to-zoom) and one-to-one trackpad scrolling (as can be witnessed with GTK3 applications like Nautilus), set the MOZ_USE_XINPUT2=1 environment variable before starting Firefox.

Troubleshooting

All Firefox extensions disabled (May 2019)

Warning: Do not delete and re-install your addons to try and fix the issue, as you will lose your addons' data.

Between 3–5 May 2019, all Firefox addons (web extensions, themes, search engines, and language packs) were mistakenly marked as Legacy addons, and could not be enabled. The bug was caused by an expired intermediate certificate.

For most users, the issue has been fixed in Firefox 66.0.4 and Firefox ESR 60.6.2. The addons should be automatically re-enabled as soon as the patched version of Firefox is installed. Certain users, such as those who have set a Master Password, might require extra steps. Please see Firefox's official support page for more information.

Firefox startup takes very long

If Firefox takes much longer to start up than other browsers, it may be due to lacking configuration of the localhost in /etc/hosts. See Network configuration#Local network hostname resolution on how to set it up.

Font troubleshooting

See Font configuration.

Firefox has a setting which determines how many replacements it will allow from fontconfig. To allow it to use all your replacement-rules, change gfx.font_rendering.fontconfig.max_generic_substitutions to 127 (the highest possible value).

Setting an email client

Inside the browser, mailto links by default are opened by a web application such as Gmail or Yahoo Mail. To set an external email program, go to Preferences > Applications and modify the action corresponding to the mailto content type; the file path will need to be designated (e.g. /usr/bin/kmail for Kmail).

Outside the browser, mailto links are handled by the x-scheme-handler/mailto mime type, which can be easily configured with xdg-mime. See Default applications for details and alternatives.

File association

See Default applications.

Firefox keeps creating ~/Desktop even when this is not desired

Firefox uses ~/Desktop as the default place for download and upload files. To change it to another folder, set the XDG_DESKTOP_DIR option as explained in XDG user directories.

Make plugins respect blocked pop-ups

Some plugins can misbehave and bypass the default settings, such as the Flash plugin. You can prevent this by doing the following:

  1. Type about:config into the address bar.
  2. Right-click on the page and select New > Integer.
  3. Name it privacy.popups.disable_from_plugins.
  4. Set the value to 2.

The possible values are:

  • 0: Allow all popups from plugins.
  • 1: Allow popups, but limit them to dom.popup_maximum.
  • 2: Block popups from plugins.
  • 3: Block popups from plugins, even on whitelisted sites.

Middle-click behavior

To use the middle mouse button to paste whatever text has been highlighted/added to the clipboard, as is common in UNIX-like operating systems, set either middlemouse.contentLoadURL or middlemouse.paste to true in about:config. Having middlemouse.contentLoadURL enabled was the default behaviour prior to Firefox 57.

To scroll on middle-click (default for Windows browsers) set general.autoScroll to true.

Backspace does not work as the 'Back' button

According to MozillaZine, the Backspace key was mapped based on which platform the browser was running on. As a compromise, this preference was created to allow the Backspace key to either go back/forward, scroll up/down a page, or do nothing.

To make Backspace go back one page in the tab's history and Shift+Backspace go forward, set browser.backspace_action to 0 in about:config.

To have the Backspace key scroll up one page and Shift+Backspace scroll down one page, set browser.backspace_action to 1. Setting this property to any other value will leave the key unmapped (Arch Linux defaults to 2, in other words, it is unmapped by default).

Firefox does not remember login information

It may be due to a corrupted cookies.sqlite file in Firefox's profile folder. In order to fix this, just rename or remove cookie.sqlite while Firefox is not running.

Open a terminal of choice and type the following:

$ rm -f ~/.mozilla/firefox/<profile id>.default/cookies.sqlite

The profile id is a random 8 character string.

Restart Firefox and see if it solved the problem.

Cannot enter/leave fullscreen

If Firefox detects an EWMH/ICCCM compliant window manager, it will try to send a WM_STATE message to the root window to request Firefox be made to enter (or leave) full-screen mode (as defined by the window manager). Window managers are allowed to ignore it, but if they do, Firefox will assume the request got denied and propagate it to the end user which results in nothing happening. This may result in not being able to full screen a video. A general workaround is to set the full-screen-api.ignore-widgets to true in about:config.

Related bug reports: Bugzilla 1189622.

"Do you want Firefox to save your tabs for the next time it starts?" dialog does not appear

From the Mozilla support site:

  1. Type about:config in the address bar.
  2. Set browser.warnOnQuit to true.
  3. Set browser.showQuitWarning to true.

Firefox detects the wrong version of my plugin

When you close Firefox, the latter saves the current timestamp and version of your plugins inside pluginreg.dat located in your profile folder, typically in ~/.mozilla/firefox/xxxxxxxx.default/.

If you upgraded your plugin when Firefox was still running, you will thus have the wrong information inside that file. The next time you will restart Firefox you will get that message Firefox has prevented the outdated plugin "XXXX" from running on ... when you will be trying to open content dedicated to that plugin on the web. This problem often appears with the official Adobe Flash Player plugin which has been upgraded while Firefox was still running.

The solution is to remove the file pluginreg.dat from your profile and that is it. Firefox will not complain about the missing file as it will be recreated the next time Firefox will be closed. [4]

JavaScript context menu does not appear on some sites

You can try setting dom.w3c_touch_events.enabled to 0 in about:config.

Firefox does not remember default spell check language

The default spell checking language can be set as follows:

  1. Type about:config in the address bar.
  2. Set spellchecker.dictionary to your language of choice, for instance en_GB.
  3. Notice that the for dictionaries installed as a Firefox plugin the notation is en-GB, and for hunspell dictionaries the notation is en_GB.

When you only have system wide dictionaries installed with hunspell, Firefox might not remember your default dictionary language settings. This can be fixed by having at least one dictionary installed as a Firefox plugin. Notice that now you will also have a tab Dictionaries in Add-ons. You may have to change the order of preferred language for displaying pages in about:preferences#general to make the spell check default to the language of the addon dictionary.

Related questions on the StackExchange platform: [5], [6], [7]

Related bug reports: Bugzilla 776028, Ubuntu bug 1026869

Some MathML symbols are missing

You need some Math fonts, namely Latin Modern Math and STIX (see this MDN page: [8]), to display MathML correctly.

In Arch Linux, these fonts are provided by texlive-core and texlive-fontsextra, but they are not available to fontconfig by default. See TeX Live#Making fonts available to Fontconfig for details. You can also try other Math fonts.

Tearing video in fullscreen mode

If you are using the Xorg Intel or Nouveau drivers and experience tearing video in fullscreen mode, try Firefox tweaks#Enable OpenGL Off-Main-Thread Compositing (OMTC).

Tearing when scrolling

Try disabling smooth scrolling in Preferences > Browsing.

Firefox WebRTC module cannot detect a microphone

WebRTC applications for instance Firefox WebRTC getUserMedia test page say that microphone cannot be found. Issue is reproducible for both ALSA or PulseAudio setup. Firefox debug logs show the following error:

$ NSPR_LOG_MODULES=MediaManager:5,GetUserMedia:5 firefox
...
[Unnamed thread 0x7fd7c0654340]: D/GetUserMedia  VoEHardware:GetRecordingDeviceName: Failed 1

You can try setting media.navigator.audio.full_duplex property to false at about:config Firefox page and restart Firefox.

This can also help if you are using the PulseAudio module-echo-cancel and Firefox does not recognise the virtual echo canceling source.

Cannot login with my Chinese account

Firefox provides a local service for Chinese users, with a local account totally different from the international one. Firefox installed with the firefox package uses the international account system by default, to change into the Chinese local service, you should install the add-on manager on this page, then you can login with your Chinese account now.

See also