Examples of whenit is essential to implement WAI-ARIA include accordions, alerts, some menus, modal and non-modal dialogs, tree views, and drag and drop. With interactive widgets, like these, an assistive technology user needs to know about changes that either may happen automatically or may happen after initiating an action.
WAI-ARIA Landmark Roles
When appropriate, WAI-ARIA landmark roles should be included to offer information about the organization of content on a page. Landmarks are:
To learn more about landmark roles, see the WAI-ARIA Authoring Practices 1.1 section on Landmark roles.
Details to Help You Get Started
Learning when to use WAI-ARIA (often called ARIA for short) can be overwhelming. There are many roles, states, and properties to understand. And it is important to include additional functionality, such as focus indication and keyboard handling, that typically "come for free" in HTML and browsers. At the same time, screen readers and browsers (in various combinations) have increasingly stable support for ARIA, but you may have to make some adjustments, depending on what versions of them you are expected to support.
Since new frameworks are created frequently, and existing ones are updated often, it is difficult to be specific, here. Instead, resources below will cover guidance from the World Wide Web consortium (W3C), along with references that are less theoretical and, perhaps, easier to understand.
Resources from the W3C
THE WAI-ARIA Overview gives some background and will orient you to the suite of documents that support the specification, including code samples. The Current Recommendation is Accessible Rich Internet Applications (WAI-ARIA 1.0); however, WAI-ARIA 1.1 is a candidate recommendation and is expected to become a full recommendation, soon. Please check the status of ARIA 1.1.
Other helpful documents from the W3C are:
- Using ARIA (including the five rules of ARIA)
- WAI-ARIA Authoring Practices 1.1
- ARIA in HTML (an HTML 5.1 specification module)
Free Video Training
Although the two video sets mentioned below cover accessibility, in general, you will find short lessons about ARIA that include screen reader demonstrations.
- Start Building Accessible Web Applications Today (course by Marcy Sutton via Eggheadio)
- A11ycasts with Rob Dodson (Google)