Firefox Accessibility Features

Firefox icon on a blue sphere

Here is a listing of some of the built in accessibility features and options that comes with Firefox along with some helpful accessibility related add-ons.

Full Page Zoom

The Full Page Zoom feature in Firefox allows you to zoom in and out of web pages including text, images and other content. Firefox provides several ways to access this feature.

Zoom Buttons
Right click on a toolbar > select Customize > Drag the Zoom Controls to the toolbar of your choice. Ctrl or Cmd + 0 to reset zoom.

Zoom Using the Keyboard
Hold down the Ctrl key (Cmd on Mac) and press the plus key to zoom in, and the minus key to zoom out. Ctrl or Cmd + 0 to reset zoom.

Zoom Using the Keyboard and Mouse
Press the Ctrl key (Cmd on Mac) and use the scroll wheel on your mouse to zoom in and out. Ctrl or Cmd + 0 to reset zoom.

To zoom text only in Firefox, press Alt v + z + t
If your Menubar is not hidden, go to View > Zoom > Zoom Text Only.

Page Zoom Buttons Add-on
For even more control of zooming, get the Page Zoom Buttons add-on for Firefox. It allows you to zoom in, zoom out, and reset zoom from a single button that can be placed on any toolbar.

Changing Fonts, Sizes, and Colors

Follow this path to access the fonts and colors control panels in Firefox.
Tools > Options > Content > Fonts & Colors.
There you will be able to select the fonts that you would like to use, the font sizes, and the colors for text, background, etc.
For finer font family and size customizations including setting a minimum font size, click on the Advanced tab.

If you would like for your settings to persist through all web pages and Firefox sessions, be sure to uncheck the option where in the advanced section it says, "Allow page's to use their own fonts, instead of my selections above".

The same goes for colors as well. Uncheck, "Allow pages to use their own colors, instead of my selections above".

Theme Font & Size Changer: Firefox Add-on

Different from add-ons and tools that allows you to enlarge the text on web pages, Theme Font & Size Changer allows you to change the global font (using your sytem's fonts) and font size for Firefox itself meaning for all windows, menus, toolbars, etc.
More information on Theme Font & Size Changer

Don't Load Images

Available through: Tools > Options > Content, uncheck "Load images automatically".
After using this option and if the author of the website has included them, you'll see and/or hear the Alt attributes text where the images would normally be displayed.

The Find Bar

Firefox has a built in search bar (aside from the default search box) for finding text and information on a web page. Hitting Ctrl+f will bring up the Find Bar at the bottom of the browser just above the Status Bar. One of the features of the Find Bar is find as you type. When you enter text into the Find Bar, text containing the letters that you type will automatically be highlighted.

When your text entry is complete, you can highlight all instances of the text on the web page at once, or one word at a time. By clicking next or previous, Firefox will take you to the highlighted text without having to scroll and search for it.
The Find bar is great for finding particular text and links on web pages, especially if the web page is long and it has a lot of info that you don't want to have to read through to find particular text and/or links.

Find As You Type

Find As You Type allows you to start finding text on a page by simply typing the text you're trying to find.
After enabling this feature, you trigger it by pressing ' (single quote) to search link text, or / (forward slash) to search all text. Find As You Type will also display the Find Bar at the bottom of the window and populate the Find field as you type.

To enable Find As You Type, go to Tools > Options > Advanced > General > Accessibility and tick the check box next to "Search for text when I start typing"
Credit: Accessibility.typeaheadfind mozillaZine Knowledge Base.
There are also links at the URL above that will teach you how to fine tune the Find As You Type feature.

FindBar Tweak Add-on

The FindBar Tweak add-on greatly enhances, and adds more functionality to the built in Find Bar.
More information on FindBar Tweak

Restricting JavaScript behavior

You can turn off JavaScript entirely by going to Tools > Options (or Preferences on Mac) > Content and unchecking "Enable JavaScript". Some web pages rely on JavaScript and may not work properly if JavaScript is disabled.

If you do not wish to disable JavaScript entirely, you can fine tune JavaScript settings to restrict the behavior of scripts. Click on the Advanced button to open the Advanced JavaScript Settings window.

The NoScript Firefox add-on gives you ultimate control over which JavaScript elements are enabled on any given page.
More information on NoScript

Browse With the Caret

Caret browsing is a way to navigate through webpages using only the keyboard by moving a text caret. A blinking cursor (the caret) is visible on all webpages allowing you to navigate through a page the same way that you might in word processor document.
Credit: Accessibility.browsewithcaret mozillaZine Knowledge Base.

You can toggle this feature on/off by pressing F7.
You can also set Firefox to always browse with the caret by going to Tools > Options > Advanced > General > Accessibility and tick the check box next to "Always use the cursor keys to navigate within web pages".

More on Firefox Accessibility

Support for native themes

Firefox integrates tightly with your native operating system's theme. If you have set certain accessibility features such as high contrast mode then Firefox will honor these settings and display correctly for you.

Support of the ARIA draft standard

Firefox supports implementations of the W3C's ARIA (Accessible Rich Internet Applications) draft standard. With ARIA support rich JavaScript widgets used in dynamic Web 2.0 applications can be made as accessible to screen reader users as they are to everyone else.
Toolkits such as the Dojo Toolkit are already successfully implementing ARIA and offering a richer Internet applications experience for visually impaired users.

Information on ARIA - Mozilla Developer Network
Information on WAI-ARIA - Overview W3C

Support for GNOME accessibility via ATK/AT-SPI

Firefox introduced accessibility to the web on the GNOME Desktop, running on the Linux or Solaris platforms. Blind and lowvision users can access the rich content the web offers today without having to leave their preferred operating environment or fall back on textbased browsers.
Using the Orca screen reader (a standard component of the GNOME desktop) users have access to all content Firefox can render. Orca offers a range of convenience features that allow you to quickly jump to headings, tables, form field elements, and others. Alternative input software such as Jambu uses this technology to allow motor-impaired surfers access to the web.
Firefox was the first browser to become accessible in a graphical environment under Linux and paves the way for many other Mozilla-based applications to follow.

Information on GNOME ATK/AT-SPI - GNOME Documentation Library
Orca Screen Reader - live.gnome.org

Improved accessibility on Windows

Firefox features IAccessible2, an extension to the well-known Microsoft Active Accessibility interface that allows screen readers to more tightly integrate with web pages. Through this technology Firefox can expose more information directly through independent interfaces.
Screen readers such as NVDA do not require the use of video interception technology to gain access to all relevant information. Voice dictation software can implement speaking of selected text without having to rely on direct screen manipulation.
Once implemented in assistive technologies, IAccessible2 support will allow a broader range of web surfers to gain access to all content that is available on the Internet.

Information on IAccessible2 - The Linux Foundation

External Firefox Accessibility Links

Firefox assistive technology compatibility
Advanced Firefox accessibility options - about config: settings.
Follow Marco Zehe's blog for the latest news and information on Firefox accessibility and technologies.

Credits

The Firefox accessibility features content on this page is being released under the following Creative Commons license.
Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0).

Created by Frank Hecker, Marco Zehe, and Ken Saunders.
Additional credit and thanks to the volunteers and maintainers of the mozillaZine Knowledge Base