About:config: Difference between revisions
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==Opening about:config== | ==Opening about:config== | ||
* In '''Firefox and Mozilla Suite/SeaMonkey''', type '''about:config''' in the Location Bar (address bar) and press Enter to display the list of preferences, as shown below in Firefox 3. | * In '''Firefox and Mozilla Suite/SeaMonkey''', type '''about:config''' in the Location Bar (address bar) and press Enter to display the list of preferences, as shown below in Firefox 3. If you see a page with the warning message, ''This might void your warranty!'', click the button labeled "I'll be careful, I promise!", to continue (in fact, there is no warranty whatsoever, it's more a joke to ensure that users are aware of what they are about to do). | ||
:[[Image:Fx3aboutconfig.png]] | :[[Image:Fx3aboutconfig.png]] | ||
* In '''Thunderbird''' 1.5 or later, about:config is accessed via "[[Menu differences in Windows, Linux, and Mac|Tools -> Options]] -> Advanced -> General -> Config Editor (button)". | * In '''Thunderbird''' 1.5 or later, about:config is accessed via "[[Menu differences in Windows, Linux, and Mac|Tools -> Options]] -> Advanced -> General -> Config Editor (button)". To access this and other about:* functions more easily in Thunderbird, you can use [https://addons.mozilla.org/thunderbird/addon/9695 ViewAbout add-on]. | ||
* For [http://www.nvu.com Nvu], there's a compatible version of the AboutConfig extension [http://glazman.org/nvu/releases/extensions/ here]. | * For [http://www.nvu.com Nvu], there's a compatible version of the AboutConfig extension [http://glazman.org/nvu/releases/extensions/ here]. | ||
Revision as of 01:32, 13 January 2011
about:config is a feature of Mozilla applications which lists application settings (known as preferences) that are read from the profile files prefs.js and user.js, and from application defaults. Many of these preferences are not present in the Options or Preferences dialog. Using about:config is one of several methods of modifying preferences and adding other "hidden" ones.
Warning: Modifying preferences can, in rare circumstances, break Firefox, Thunderbird or the Mozilla Suite, or can cause strange behavior. Only do so if you know what you are doing or are following trustworthy advice.
Opening about:config
- In Firefox and Mozilla Suite/SeaMonkey, type about:config in the Location Bar (address bar) and press Enter to display the list of preferences, as shown below in Firefox 3. If you see a page with the warning message, This might void your warranty!, click the button labeled "I'll be careful, I promise!", to continue (in fact, there is no warranty whatsoever, it's more a joke to ensure that users are aware of what they are about to do).
- In Thunderbird 1.5 or later, about:config is accessed via "Tools -> Options -> Advanced -> General -> Config Editor (button)". To access this and other about:* functions more easily in Thunderbird, you can use ViewAbout add-on.
- For Nvu, there's a compatible version of the AboutConfig extension here.
Adding modifying and resetting preferences
To add a new preference, context-click (right-click) anywhere in the list of preferences. In the context menu, select New then select the type of preference you are adding.
- String is any sequence of text
- Integer is a number
- Boolean is true-false
To modify an existing preference, context-click (right-click) on the preference, select Modify and type in the new value. In some cases, Toggle will be the selection offered for boolean (true-false) preferences.
To reset a preference to its default value or to remove an added preference, context-click (right-click) on the preference and select Reset. If you added the entry via about:config, the preference will no longer be listed after restarting the program. (For more information about resetting preferences, see this article).
Filter bar
You can use the Filter bar at the top of the about:config page to filter the preferences that you want to inspect. Starting with Firefox 3, the Filter bar also accepts wildcards and a regular expression in the form of /regexp/i
to filter preferences. [1] The i switch is for ignore case. That is the default for normal searches, but you need to specify it if you want the RegExp match to be case insensitive. The RegExp tests for a match of name;value of a preference.
Some examples:
security*ssl security*ssl*rsa security*tls /^security[.]ssl3.*rsa|security[.].*tls/i /^security[.]ssl3.*(128|256)/i /^(?!gecko[.]handler|network[.]IDN|network[.]protocol|print|security[.]ssl)/i /^(?=browser[.]|dom[.]|network[.](?!IDN|protocol))/i
See also
- The article about:config entries contains a list of valid about:config entries and their possible values. The article is a reference for what each preference does; it is not the place to actually edit your preferences! (See the section Opening about:config above.)
- Editing configuration
- About protocol links — other about: pages.
External links
- A Brief Guide to Mozilla Preferences - MDC
- How To Modify Hidden Preferences Using about:config — MozillaZine's step by step guide with screenshots (from web.archive.org)
- Mozilla Help: Editing Configuration files — (from ilias.ca)
- Preferential extension — An extension similar to about:config with extra features, such as documentation for some preferences.