Not only are there add-ons to customize
Firefox, but there are other built in features and tools that
allow you to customize and use Firefox in a way
that best suits your needs. Here is a listing of some of the built in
accessibility features and options that come with Firefox.
Also see - the new accessibility features in Firefox 3.
Changing Fonts, Sizes, and Colors
Follow this path to access the fonts and colors control panel in Firefox. Tools, Options, Content, Fonts and Colors. There you will be able to select the fonts that you would like to use and also the sizes and web page colors.
If you would like for your settings to persist through all web pages and Firefox sessions for fonts, be sure to un-check 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 goes for colors as well. Un-check, "Allow pages to use their own colors, instead of my selections above".
Don't Load Images
Available through: Tools, Options, Content, uncheck "Load images automatically". This may be helpful for users with screen readers and those who have no use for images on web pages. 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 Google 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 highlight.
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.
Turning Off Java applets
Some web pages provide a rich interactive experience with Java applets. However, some users that rely on keyboard navigation may experience problems with some Java applets that automatically set focus and do not provide a way to "break out" of the applet and navigate to the rest of the web page. If this is a problem for you, you can disable Java by going to Tools Options (or Preferences on Mac), selecting the "Content" and unchecking the "Enable Java" option.
Restricting JavaScript behavior
You can turn off JavaScript entirely by going to Tools Options (or Preferences on Mac), selecting the "Content" panel, 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, there are also a number of advanced JavaScript settings to restrict the behavior of scripts. Immediately after the "Enable JavaScript" checkbox, click the "Advanced" button to open the "Advanced JavaScript Settings" window. Here you can control whether scripts are allowed to move or resize existing windows, raise or lower windows, disable or replace context menus, hide the status bar, or change status bar text.
Firefox Keyboard and Mouse Shortcuts
The shortcuts available for Firefox navigation will reduce the need for you to reach for your mouse or keyboard. Access Firefox provides these printable shortcuts for you to study online or to download in PDF or ODT formats. Firefox Shortcuts Page
External Firefox Accessibility Links
More built in accessibility features in Firefox on Mozilla.org.
Firefox assistive technology compatibility for Firefox 2.0 - 3.0.
Advanced Firefox accessibility options - about config: settings.
