About screen readers

A screen reader is a type of user interface that interprets content on a screen and reads the environment aloud to the user. There are many options for screen readers of varying abilities and popularity. Two of the most popular are JAWS by Freedom Scientific and NVDA by NV Access.

Screen reader technology relies on a combination of a web browser’s Accessibility API and Web Accessibility Initiative – Accessible Rich Internet Applications (WAI-ARIA) overrides to decipher the web application’s structure and content. An Accessibility API is built into a browser to expose public properties and methods to retrieve information about the Document Object Model (DOM) of a web application or page. WAI-ARIA consists of HTML tag attributes that provide the means to override the Accessibility API and provide meaning to content that the Accessibility API is unable to interpret. This is especially important with dynamic AJAX content and generic HTML tags like the <div> tag being used to house content, which does not indicate to the browser how it is being used or what type of content it contains. While all major web browsers base their Accessibility APIs on similar interpretations to the DOM, they sometimes deviate from one another. There are also differences between each browser’s support for WAI-ARIA. Therefore, different combinations of various screen readers and web browsers yield varying results. For this reason, it is important to understand that by applying best practices when creating a form, your chances of consistent usability increase.

A web browser’s Accessibility API and support for WAI-ARIA provide the information for a screen reader to interpret and speak the content. Some screen reader vendors recommend a particular browser for use with their product. Freedom Scientific recommends using JAWS with Internet Explorer and NVDA recommends using Mozilla Firefox. However, JAWS and NVDA both provide support for most browsers. JAWS reads and interacts with the Mongoose web client best when using Firefox. For this reason, if using JAWS, design and test forms using Firefox.

Browsers and screen readers release newer versions and apply updates, so these ideal combinations can change. Ultimately, it is up to end users to decide what combination works best for them.