Screen readers work with the accessibility API of the operating system and browser
The operating system has an accessibility API which conveys information about the names, roles, values, and structure of web content, plus events that should be announced to users. Browsers have additional accessibility architecture features which screen readers can detect and interpret, then pass on to screen reader users.
UI Automation is the modern accessibility API in Windows.
1: Google Chrome and JAWS
The best screen reader and browser combination is JAWS and Google Chrome.
2: Firefox and NVDA
The second most popular screen reader and browser combination is NVDA and Firefox. NVDA provides a useful tool called the Speech Viewer that allows for those testing the page to easily view the screen reader output and find errors. This makes the Firefox and NVDA combination quite useful.
Mobile screen readers:
- VoiceOver with Safari (iOS)
- TalkBack with Firefox (Android)
It is important to test with both VoiceOver with Safari (iOS) and TalkBack with Firefox (Android) because users widely use both products, and the two programs have different advantages and abilities. So it is important to make websites accessible for both mediums.
Other browsers and screen readers
For most web sites, it is practically safe to say that testing and fixing accessibility issues in Chrome/JAWS and Firefox/NVDA is enough to find the common accessibility issues. In fact, from a practical perspective, one screen reader and browser combination is almost always enough when testing standard, non-interactive web content like paragraphs, images, tables, headings, landmarks, form structure, links, and so on.
Interactive content — like form validation and custom JavaScript/ARIA widgets — can be complicated, because that is where the differences between screen readers and browsers (including bugs or lack of accessibility support for certain techniques) is most likely to happen. It is useful to test interactive content in multiple screen reader and browser combinations.
Note:
- Some screen readers support multiple browsers to some degree, but all screen readers work best when paired with their favored browser (in accordance with the lists above).
- Capturing screen reader output with NVDA
NVDA’s Speech Viewer provides an easy way to capture output which can be copied and pasted into bug reports. To turn on Speech Viewer, activate the NVDA icon in the system tray, then select Tools > Speech Viewer.
