How to turn on accessibility features in Mozilla Firefox

Magnify your screen

This feature will increase and decrease the size of text and images on the screen for better visibility.

Press and hold down the CTRL key on your keyboard.
At the same time as holding the CTRL key:
- press the + key to increase the size of the text and images or
- press the ‘-‘ key to decrease the size of the text and images.
Keep repeating Step 2 until you reach the desired size.

Select the Tools menu (Shortcut: ALT + T).
Select Options (Shortcut: O).
Select the Content option which is in the top-middle of the menu.
Select the Colors button in the middle, right-hand side of the Options box (Shortcut: ALT + C).
Choose your desired colours by selecting the colour box and then choosing from the available colours. You can change the colours for text, background, and visited and unvisited hyperlinks.
Uncheck the box next to Allow pages to choose their own colors, instead of my selections above (Shortcut: ALT + A).
Select OK on the Colors screen.
Select OK on the Options screen.

Select the Tools menu (Shortcut: ALT + T).
Select Options (Shortcut: O).
Select the Content option which is in the top-middle of the menu.
Under Fonts & Colors, use the drop-down menus to select the font and font size of your choice.

To disable custom fonts (if a website uses them):

Select the Advanced button in the middle, right-hand side of the Options box (Shortcut: ALT + A).
Select the web page font and/or plain text font you want to use from the drop-down list.
Uncheck the box next to Allow pages to choose their own fonts, instead of my selections above (Shortcut: ALT + A).
Select OK on the Advanced screen.

Then:

Select the Tools menu (Shortcut: ALT + T)
Select Options(Shortcut: O).
Select the Advanced option which is on the right of the top menu.
Under Accessibility, choose your desired options from:
- Always use the cursor keys to navigate within pages (Shortcut: ALT + C)
- Search for text when I start typing (Shortcut: ALT + X)
- Warn me when websites try to redirect or reload the page (Shortcut: ALT + B)
Select OK on the Options screen.

Mozilla’s information about accessibility features in Firefox.
Mozilla Wiki detailing assistive technology products and their compatibility with Firefox.
My Web, My Way provides tools and information to assist people with a disability to get the most out of the Internet. Includes practical how-to articles for Windows, Mac and Linux.