Hacking Firefox: The secrets of about:config User Interface

Make the user interface behave

Another big reason people hack Firefox's settings is to modify the user interface -- either to make it a little easier to do something, or to revert to a behavior that was prevalent in Version 1.x but changed in 2.0.

Get case-sensitive, in-page searches
The integer preference accessibility.typeaheadfind.casesensitive controls how Firefox's "Find as You Type" feature behaves. The default is 0 for case-insensitive searches; set it to 1 for case-sensitive matching.

Control address bar searches
You may have noticed that if you type something into Firefox's address bar that's not an address (a "keyword"), Firefox typically passes it on to Google as an "I'm Feeling Lucky" search term. The exact search engine string to use is defined in the string preference keyword.URL; if you want to change it to something else, you can simply edit this string.

For instance, to make Microsoft's Live.com the default keyword search, set this string to
http://search.live.com/results.aspx?q=

For a Yahoo search, it would be
http://search.yahoo.com/search?p=

If you want to restore the default search, use
http://www.google.com/search?ie=UTF-8&oe=
UTF-8&sourceid=navclient&gfns=1&q=

Finally, if you want to turn this address-bar keyword functionality off altogether, set the Boolean preference keyword.enabled to false.

Note that with Google, the more generic the keyword, the less likely it is to be used as an "I'm Feeling Lucky" search -- although what constitutes "generic" isn't always clear. For instance, typing "clean" into the address bar returns a generic Google search page, but "sideways" takes me to the Internet Movie Database entry for the movie of that name (the "I'm Feeling Lucky" result). Your mileage will almost certainly vary.

Select just a word
The Boolean preference layout.word_select.eat_space_to_next_word governs one of Firefox's tiny, but for me incredibly annoying, little behaviors. When you double-click on a word in a Web page to select it, Firefox automatically includes the space after the word. Most of the time I don't want that; I just want the selection to stop at the end of the word. Setting this to false will defeat that behavior.

Select a word and its punctuation
Somewhat contrarily, if you double-click a word that's next to any kind of punctuation mark, Firefox defaults to selecting only the word itself, not its adjacent punctuation. Set the Boolean preference layout.word_select.stop_at_punctuation to false to select the word and its adjacent punctuation.

Get Alt-hotkey shortcuts back
One minor change in Firefox 2 was the way in which form elements on a Web page had hotkey bindings assigned to them. In Firefox 1.x, when a Web page assigned a hotkey to a form element, you pressed Alt-hotkey to access it. In Version 2.x, this was changed to Alt-Shift-hotkey. To revert to the original 1.x behavior, set the integer preference ui.key.contentAccess to 4. This is useful if you have, for instance, a Web-based interface you spend a lot of time in, and use Alt-key bindings to do things quickly in that particular page.

Note that one possible consequence of setting this back to the old behavior is that Alt-key bindings on a Web page can now override the default key sequences for the program itself (such as Alt-S for History), but you can always get around this by tapping Alt to activate the menu and then tapping the program hotkey in question.

Change scrollbar behavior
By default, clicking in the empty areas of the Firefox window's scrollbar will simply cause the view to move up or down one page. You can change this behavior by creating a Boolean preference called ui.scrollToClick and setting its value to true. Now clicking in a scrollbar will cause the view to jump directly to that point in the page (basically the same as dragging the scrollbar to that position).

Get click-and-hold context menus back (for Macs only)
If you want to restore the classic click-and-hold context-menu behavior on the Macintosh, edit or create the Boolean preference ui.click_hold_context_menus and set it to true.

Hacking Firefox: The secrets of about:config Tabbed Browsing

Have tabbed browsing your way

Right from the start, one of Firefox's strengths has been tabbed browsing. But if the tabs don't behave quite the way you want them to by default, or you hate the way the default behaviors have changed since Firefox 1.x, the following changes will bring them in line.

Corral close buttons
The integer preference browser.tabs.closeButtons controls how the close buttons (the "X" icons) are rendered on tabs:

0: Display a close button only on the currently active tab. This is a nice way to keep from accidentally smacking into a close button for the wrong tab.

(You can press Ctrl-F4 to close only the current tab, but many mouse-centric people never bother to do this.)

1: Display close buttons on all tabs (default).

2: Don't display any close buttons; the only way to close a tab is by pressing Ctrl-F4.

3: Display one close button at the end of the tab bar (Firefox 1.x's default).

A close button on just one tab. (Click for larger view.)

Open search results in a new tab
This one is a favorite of mine. When browser.search.openintab (a Boolean preference) is set to true, any searches launched from the Search tool bar are opened in a new tab instead of overwriting the contents of the current one. I can't tell you the number of times I mistakenly wiped out my current page before I started using this.

Note that if you launch a new browser window with Ctrl-N and perform a search there, you'll see the search results and the default home page for the new browser instance loading in separate tabs.

Open bookmark groups in new tabs
If you open a group of bookmarks at once, Firefox's default behavior is to replace any existing tabs with the newly opened pages. Set browser.tabs.loadFolderAndReplace (Boolean) to false, and opening groups of bookmarks will append new tabs to the existing window instead of overwriting existing ones.

Squeeze more tabs into the tab bar
The integer preference browser.tabs.tabMinWidth controls how narrow, in pixels, tabs can be shrunk down before scroll arrows appear on the left and right edges of the tab bar.

The default is 100, but you can set this to something smaller so you can fit more tabs in the bar at once. Note, however, that you might find the shortened titles harder to read.

The tab bar before and after reducing the minimum tab width. (Click for larger view.)

In the same vein, the integer preference browser.tabs.tabClipWidth sets the minimum width, in pixels, that a tab must be in order to show a close button. This is 140 by default, so if you set this to something lower, you'll see more tabs with close buttons when the tab bar is heavily populated.

Hacking Firefox: The secrets of about:config Speed up

Speed up page display

Some of the more recent Firefox customizations I've examined are ways to speed up the rendering of Web pages. The settings to do this are a little arcane and not terribly self-explanatory, but with a little tinkering, you can often get pages to pop up faster and waste less time redrawing themselves.

Start rendering pages faster
Creating an nglayout.initialpaint.delay integer preference lets you control how long Firefox waits before starting to render a page. If this value isn't set, Firefox defaults to 250 milliseconds, or 0.25 of a second. Some people report that setting it to 0 -- i.e., forcing Firefox to begin rendering immediately -- causes almost all pages to show up faster. Values as high as 50 are also pretty snappy.

Reduce the number of reflows
When Firefox is actively loading a page, it periodically reformats or "reflows" the page as it loads, based on what data has been received. Create a content.notify.interval integer preference to control the minimum number of microseconds (millionths of a second) that elapse between reflows. If it's not explicitly set, it defaults to 120000 (0.12 of a second).

Too many reflows may make the browser feel sluggish, so you can increase the interval between reflows by raising this to 500000 (500,000, or 1/2 second) or even to 1000000 (1 million, or 1 second). If you set this value, be sure to also create a Boolean value called content.notify.ontimer and set it to true.

A page "reflowing" while loading in Firefox.

Control Firefox's 'unresponsive' time
When rendering a page, Firefox periodically runs a little faster internally to speed up the rendering process (a method Mozilla calls "tokenizing"), but at the expense of being unresponsive to user input for that length of time. If you want to set the maximum length of time any one of these unresponsive periods can be, create an integer preference called content.max.tokenizing.time.

Set this to a multiple of content.notify.interval's value, or even the same value (but higher is probably better). If you set this to something lower than content.notify.interval, the browser may respond more often to user input while pages are being rendered, but the page itself will render that much more slowly.

If you set a value for content.max.tokenizing.time, you also need to create two more Boolean values -- content.notify.ontimer and content.interrupt.parsing -- and set them both to true.

Control Firefox's 'highly responsive' time
If Firefox is rendering a page and the user performs some kind of command, like scrolling through a still-loading page, Firefox will remain more responsive to user input for a period of time. To control how long this interval is, create an integer preference called content.switch.threshold.

This is normally triple the value of content.notify.interval, but I typically set it to be the same as that value. Set it to something very low -- say, 10000 (10,000 microseconds) -- and the browser may not respond as snappily, but it may cause the rendering to complete more quickly.

If you haven't already created the Boolean values content.notify.ontimer and content.interrupt.parsing and set them both to true in conjunction with content.max.tokenizing.time, you'll need to do so to make content.switch.threshold work properly.

If you are more inclined to wait for a page to finish loading before attempting to do anything with it (like scroll through it), you can set content.max.tokenizing.time to a higher value and content.switch.threshold to a lower value to allow Firefox to finish rendering a page faster at the expense of processing user commands. On the other hand, if you're the kind of person who likes to scroll through a page and start reading it before it's done loading, you can set content.max.tokenizing.time to a lower value and content.switch.threshold to a higher one, to give you back that much more responsiveness at the cost of page-rendering speed.

Hacking Firefox: The secrets of about:config

Discover more than 20 behind-the-scenes tweaks for speeding up page loads, reducing memory drain and making the interface behave the way you want it

Ever since its debut, Firefox has garnered a reputation for being an enormously customizable program, both through its add-on architecture and its internal settings. In fact, many of Firefox's settings aren't exposed through the Tools > Options menu; the only way to change them is to edit them manually. In this article, we'll explore some of the most useful Firefox settings that you can change on your own and that aren't normally available through the program's graphical interface.

The closest analogy to how Firefox manages its internal settings is the Windows Registry. Each setting, or preference, is given a name and stored as a string (text), integer (number) or Boolean (true/false) value. However, Firefox doesn't keep its settings in the registry, but in a file called prefs.js. You can edit prefs.js directly, but it's often easier to change the settings through the browser window.

Type about:config in the address bar and press Enter, and you'll see all the settings currently enumerated in prefs.js, listed in alphabetical order. To narrow down the hundreds of configuration preferences to just the few you need, type a search term into the Filter: bar। (Click the Show All button or just clear the Filter: bar to get the full list back again.)

get the full list back again.)

The about:config page. (Click for larger view.)

To edit a preference, double-click on the name and you'll be prompted for the new value. If you double-click on an entry that has a Boolean value, it'll just switch from true to false or vice versa; double-click again to revert to the original setting. Not all changes take effect immediately, so if you want to be absolutely certain a given change is in effect, be sure to close and reopen Firefox after making a change.

Editing a preference. (Click for larger view.)

Note that not every setting in about:config exists by default. Some of them have to be created manually. If you want to add a new preference, right-click somewhere on the page and select New, then select the type of item to create (String, Integer or Boolean) and supply the name and value.

Before you begin

Here are a few caveats to keep in mind as you explore and tweak:

Not everyone will get the same benefits by enabling these tweaks. This is especially true for changing the network settings. If you habitually visit sites that don't allow a large number of connections per client, for instance, you won't see much benefit from raising the number of connections per server.

Some hacks may have a limited shelf life. With each successive release of Firefox, the need for tweaking any of the performance-related config settings (like the network settings) may dwindle as Firefox becomes more self-tuning based on feedback from real-world usage scenarios. In short, what works now may not always work in the future -- and that might not be a bad thing.

Keep a log of everything you change, or make backups. If you tweak something now and notice bizarre activity in a week, you'll want to be able to track back to what was altered and undo it. Firefox does show which about:config changes have been set manually, but this isn't always the most accurate way to find out what you changed.

To make a backup of your preferences in Firefox, just make a copy of the file prefs.js, which is kept in your Firefox profile folder. If you mess something up, you can always copy this file back in. (Be sure to shut down Firefox before making a copy of prefs.js or moving a copy back into the profile folder!)

In Windows XP, the profile folder is
\Documents and Settings\\Application Data\Mozilla\Firefox\Profiles\.default\

In Windows Vista, this folder is
\Users\\AppData\Roaming\Mozilla\Firefox\Profiles\.default\

Note that Application Data and AppData are hidden folders by default, so they may not show up unless you force Explorer to show hidden objects. (Open the Control Panel, double-click Folder Options, select the View tab, select "Show hidden files and folders" and click OK.)

In Mac OS X, the profile folder is
/Library/Application Support/Firefox/Profiles/.default/

and in Linux it's
~/.mozilla/firefox/.default/

but on those platforms it's usually quicker simply to search for prefs.js.

Alternatively, you can use the handy Firefox Extension Backup Extension (FEBE). It backs up not only the prefs.js file but just about every other thing in Firefox -- extensions, themes, cookies, form history and so on.