Radix Primitives follow the WAI-ARIA authoring practices guidelines and are tested in a wide selection of modern browsers and commonly used assistive technologies.
We take care of many of the difficult implementation details related to accessibility, including aria and role attributes, focus management, and keyboard navigation. That means that users should be able to use our components as-is in most contexts and rely on functionality to follow the expected accessibility design patterns.
WAI-ARIA, published and maintained by the W3C, specifies the semantics for many common UI patterns that show up in Radix Primitives. This is designed to provide meaning for controls that aren't built using elements provided by the browser. For example, if you use a div instead of a button element to create a button, there are attributes you need to add to the div in order to convey that it's a button for screen readers or voice recognition tools.
In addition to semantics, there are behaviors that are expected from different types of components. A button element is going to respond to certain interactions in ways that a div will not, so it's up to the developer to reimplement those interactions with JavaScript. The WAI-ARIA authoring practices provide additional guidance for implementing behaviors for various controls that come with Radix Primitives.
With many built-in form controls, the native HTML label element is designed to provide semantic meaning and context for corresponding input elements. For non-form control elements, or for custom controls like those provided by Radix Primitives, WAI-ARIA provides a specification for how to provide accessible names and descriptions to those controls.
Where possible, Radix Primitives include abstractions to make labelling our controls simple. The Label primitive is designed to work with many of our controls. Ultimately it's up to you to provide those labels so that users have the proper context when navigating your application.
Many complex components, like Tabs and Dialog, come with expectations from users on how to interact with their content using a keyboard or other non-mouse input modalities. Radix Primitives provide basic keyboard support in accordance with the WAI-ARIA authoring practices.
Proper keyboard navigation and good labelling often go hand-in-hand with managing focus. When a user interacts with an element and something changes as a result, it's often helpful to move focus with the interaction so that the next tab stop is logical depending on the new context of the app. And for screen reader users, moving focus often results in an announcement to convey this new context, which relies on proper labelling.
In many Radix Primitives, we move focus based on the interactions a user normally takes in a given component. For example, in AlertDialog, when the modal is opened, focus is programatically moved to a Cancel button element to anticipate a response to the prompt.