Firefox.

How edit settings?

Default settings stored in 'prefs.js'. If you don't want rewrite it edit/create 'user.js':

$ emacs ~/.mozilla/firefox/xxxxxxx.default/user.js

or open link:

about:config

See:

• http://www.mozilla.org/unix/customizing.html#prefs

Profiles.

$ firefox -P

c:/Users/%USERNAME%/AppData/Roaming/Mozilla/Firefox/profiles.ini

[Profile1]
Name=test
IsRelative=0
Path=E:\home\.firefox

$ firefox             # run firefox with default profile
$ firefox -P second-profile-name -no-remote
$ firefox -P third-profile-name -no-remote

https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options
  Firefox command line options.

[Profile<N>]
Name=default
IsRelative=1
Path=Profiles/xxxxxxx.default
Default=1

Change user agent.

general.useragent.override

For Debian Icewasel just remove Icewasel from user agent string. Example:

Mozilla/5.0 (X11; Linux x86_64; rv:44.0) Firefox/44.0

How to prevent links from opening a new window?

Go to about:config and set:

browser.link.open_newwindow - 3. May be 1:cur 2:win 3:tab
browser.link.open_external - 3. May be 1:cur 2:win 3:tab
browser.link.open_newwindow.restriction - 0. May be 0, 1. 2

See also:

• http://kb.mozillazine.org/Browser.link.open_external
• http://kb.mozillazine.org/Browser.link.open_newwindow.restriction

How to prevent links from resize window?

Preference -> Content -> JavaScript ->
              Advanced -> disable "Move and resize existing windows"

How limit simultaneously connection counts?

network.http.max-connections - 4

or search by word 'connections' in 'about:config'.

See:

• http://kb.mozillazine.org/Network.http.max-connections

Copy link without escaping non ASCII chars.

Run about:config and set network.standard-url.escape-utf8 to false.

Firefox downloading.

ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/

Download older version.

Privacy.

See:

• http://www.mozilla.com/en-US/privacy-policy.html
• http://www.mozilla.com/en-US/legal/privacy/firefox-en.html

browser.safebrowsing.enabled  "false"
              do not use safebrowsing
browser.safebrowsing.malware.enabled "false"
              do not download malware blacklists and do not check downloads
browser.safebrowsing.remoteLookups "false"
              use local blacklist to determine a site's phishiness instead
              submitting the URL to a third party (deprecated?)

View_source.

view_source.wrap_long_lines

True - HTML code will wrap in the view source window, false (default).

view_source.syntax_highlight

True (default) - enable syntax highlighting in the view source window. "View → Syntax Highlighting".

Privacy.

privacy.item.cache

True (default) - clear the cache when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.cookies

True - delete all cookies when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.downloads

True (default) - clear history of downloaded files when using the Clear Private Data feature (Firefox 1.5 and above only). Note: This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.formdata

True (default) - clear all saved form data when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.history

True (default) - clear the browsing history when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.offlineApps

True - clear the offline website data when using the Clear Private Data feature (Firefox 3 and above only). This can be changed via "Tools → Options → Privacy / Private Data → Settings...".

privacy.item.passwords

True - delete all saved passwords when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.item.sessions

True (default) - clear all authenticated SSL sessions when using the Clear Private Data feature (Firefox 1.5 and above only). This can be changed via "Tools → Options → Privacy → Settings..." (Firefox 1.5) or "Tools → Options → Privacy / Private Data → Settings..." (Firefox 2.0 and above).

privacy.popups.firstTime

True (default) - the user has never hidden the popup blocker notification bar before, so show a dialog explaining the status bar icon. False - the user has been informed of the status bar icon.

privacy.popups.policy

Determines the popup blocker behavior. 1 - allow popups, 2 - reject popups. Seems to be deprecated in favor of dom.disable_open_during_load.

privacy.popups.showBrowserMessage

True (default) - display a message at the top of the browser window when a popup has been blocked. False - display a status bar icon to indicate when a popup has been blocked.

privacy.sanitize.promptOnSanitize

True (default) - prompt before performing the Clear Private Data operation (Firefox 1.5 and above only) In Firefox 1.5 and above, this can be changed via "Tools → Options → Privacy → Settings...".

privacy.sanitize.sanitizeOnShutdown

True: Perform the Clear Private Data operation when closing the browser (Firefox 1.5 and above only). Note: In Firefox 1.5 and above, this can be changed via "Tools → Options → Privacy → Settings..."

Security

security.warn_entering_secure

True (default) - display a dialog warning the user when entering a secure site from an insecure one.

security.warn_entering_secure.show_once

True (default) - Leave the "Alert me whenever..." box unchecked on the security warning dialog.

security.warn_entering_weak

True (default) - display a dialog warning the user when entering an insecure site from a secure one.

security.warn_entering_weak.show_once

True (default) - leave the "Alert me whenever..." box unchecked on the security warning dialog.

security.warn_leaving_secure

True (default) - display a dialog warning the user when leaving a secure site.

security.warn_leaving_secure.show_once

True (default) - leave the "Alert me whenever..." box unchecked on the security warning dialog.

security.warn_submit_insecure

True (default) - display a dialog warning the user when submitting a form to an insecure site.

security.warn_submit_insecure.show_once

True (default) - leave the "Alert me whenever..." box unchecked on the security warning dialog.

security.warn_viewing_mixed

True (default) - display a dialog warning the user when a page has both encrypted and non-encrypted content.

security.warn_viewing_mixed.show_once

True (default) - leave the "Alert me whenever..." box unchecked on the security warning dialog.

security.xpconnect.plugin.unrestricted

True (default) - allow scripting of plugins by untrusted scripts.

Signon.

signon.prefillForms

True (default) - allows auto-filling of stored usernames and passwords on webpage forms.

signon.rememberSignons

True (default) - enable the Password Manager.

JavaScript.

javascript.enabled (Boolean).

Set this to true should you desire support for JavaScript. The same as the Enable JavaScript option in the Content tab.

dom.allow_scripts_to_close_windows (Boolean).

Setting this to true specifies that any window may be closed and isn’t recommended. Entering false specifies that only windows opened by script can be closed via close().

dom.disable_image_src_set (Boolean).

This option determines whether JavaScript is allowed to change images. Set this to true to enable this feature and false to disable it (recommended).

dom.disable_open_click_delay (Integer).

This option specifies the amount of time, in milliseconds, that must be surpassed before a pop-up window created by JavaScript setInterval() or setTimeout() calls aren’t managed by current pop-up blocker settings. Beneath this threshold existing pop-up blocker settings are applied. Default is 1000 (1 second).

dom.disable_open_during_load (Boolean).

Set this to true to enable Firefox’s built-in pop-up blocker, which disables the loading of much pop-up content on sites – which will mostly be advertisements (it’s worth noting this is not perfect and will also disable many legitimate pop-ups). Should a pop-up be blocked in this way an information bar will appear at the top of the window, from which you can select what action to take. Setting this to false disables the pop-up blocker (Not recommended). Note – This is the same as the Block pop-up windows option in the Options menu, Content tab.

dom.disable_window_flip (Boolean).

This option controls whether JavaScript may be used to bring windows into the foreground/background via focus(). Setting this to true disables such actions, which won’t affect new pop-ups from loading in the foreground, though can force existing ones to remain in the background unless switched to manually. Set this to false to allow the script to determine what happens. Note – This is the same as the Raise or lower windows option in Advanced JavaScript Settings.

dom.disable_window_move_resize (Boolean).

This option controls whether JavaScript can be used to move &/or resize windows, whereby setting this to false enables scripts to do this. It would perhaps be best to set this to true, allowing only yourself to resize/move windows. Note – This is the same as the Move or resize existing windows option in Advanced JavaScript Settings.

dom.disable_window_open_feature.close (Boolean).

Set this to false to enable the use of scripting to hide the close button of windows, true forces the close button to always be displayed (recommended).

dom.disable_window_open_feature.directories (Boolean).

Set this to false to enable the use of scripting to hide the bookmarks toolbar, true prevents the bookmarks toolbar from being hidden in this way.

dom.disable_window_open_feature.location (Boolean).

Set this to false to enable the use of scripting to hide the Location (Address) bar, true prevents the Address bar from being hidden.

dom.disable_window_open_feature.menubar (Boolean).

Set this to false to enable the use of scripting to hide the Menu bar, true disables the hiding of the Menu bar.

dom.disable_window_open_feature.minimizable (Boolean).

Set this to false to enable the use of scripting to disable the minimizing of windows, true enables the minimizing of such windows (recommended).

dom.disable_window_open_feature.resizable (Boolean).

Set this to true to enable the use of scripting to hide the close button of windows, false forces the close button to always be displayed (recommended).

dom.disable_window_open_feature.scrollbar (Boolean).

Set this to false to enable the use of scripting to hide the Scroll bar in windows, true disables the hiding of the Scroll bar in windows.

dom.disable_window_open_feature.status (Boolean).

This option controls whether JavaScript can be used to hide the status bar, whereby setting this to false enables scripts to do this. Set this to true to force the status bar to be displayed at all times. Note – This is the same as the Hide the status bar option in Advanced JavaScript Settings.

dom.disable_window_open_feature.titlebar (Boolean).

Set this to false to enable the use of scripting to hide the Title bar of windows, true forces the Title bar to always be displayed.

dom.disable_window_open_feature.toolbar (Boolean).

Set this to false to enable the use of scripting to hide the Navigation toolbar, i.e. Back, Forward, etc. buttons, false prevents the hiding of the Navigation toolbar.

dom.disable_window_status_change (Boolean).

This option controls whether JavaScript can be used to display custom text in the status bar, e.g. moving the mouse over a hyperlink normally would display where the link points to, though a script could be used to display something else instead. Set this to false to allow such custom status bar text displayed, while true will disable this. Note – This is the same as the Change status bar text option in Advanced JavaScript Settings.

dom.event.contextmenu.enabled (Boolean).

This option controls whether JavaScript can be used to alter, or even disable the context menu, e.g. right clicking could be disabled on certain pages. Set this to true if you wish to allow sites to be able to do this, while false ensures scripts can’t be used to alter this functionality. Note – This is the same as the Disable or replace context menus option in Advanced JavaScript Settings.

dom.max_script_run_time (Integer).

This specifies the amount of time, in seconds, that a script in content may run before being prompted whether to continue running it or not (default 10). Setting to 0 allows scripts to run as long as required.

dom.max_chrome_script_run_time (Integer).

This specifies the amount the amount of time, in seconds, that a script with chrome privileges may run before being prompted whether to continue running it or not (default 20).

dom.popup_maximum (Integer).

This value specifies the maximum number of pop-up windows that may be open simultaneously (default 20).

See

• http://kb.mozillazine.org/Dom.max_script_run_time
• http://kb.mozillazine.org/Dom.max_chrome_script_run_time

Plugin.

plugin.default_plugin_disabled

True (default) - when a plugin is needed, prompt the user. False - don't prompt the user to install needed plugins.

plugin.expose_full_path

True - in about:plugins and navigator.plugins, reveal the full path to plugin files. False (default) - show only the plugin filename

Download Manager.

browser.download.manager.flashCount

Set to 0 to stop flashing Download Manager.

browser.download.manager.showAlertOnComplete

Set to false to top flashing alter on complete download.

browser.download.manager.retention

Clear immediately the download history: 0 - upon successful download 1 - when the Firefox browser closes 2 - needs user to clear it manually (default)

browser.download.manager.closeWhenDone

Set to false to stop Firefox closing Download Manager when download is complete.

browser.download.manager.scanWhenDone

Set to false to stop scaning for viruses.

Search.

Useful user plugin.

How to disable GZIP compression in Firefox?

user_pref("network.http.accept-encoding", ""); // default - "gzip,deflate".

Restart the Firefox in Safe Mode.

Poorly designed or incompatible extensions can cause problems with your browser, including make it crash, slow down page display, etc:

$ firefox -safe-mode

Hot calc by Firefox.

At URI type some thing like "javascript: 4+5"

Disable safe browsing.

user_pref("browser.safebrowsing.enabled", false);
user_pref("browser.safebrowsing.malware.enabled", false);
user_pref("services.sync.prefs.sync.browser.safebrowsing.enabled", false);
user_pref("services.sync.prefs.sync.browser.safebrowsing.malware.enabled;false", false);

Disable geo location.

user_pref("geo.enabled", false);

You can fake your location by JSON like:

{"location":{"latitude":48.861426,2.338929,"longitude":2.338929, "accuracy":20.0}}

in file pointed by:

user_pref("geo.wifi.uri", "file:///home/user/fake-geo.json");