What do ARIA roles do in web accessibility?

ARIA roles enhance accessibility by providing additional context for assistive technologies, which is crucial for users with disabilities. These roles allow developers to define ways in which users can interact with web content more effectively. They act as additional descriptors that inform assistive technologies, such as screen readers, about the nature and purpose of the elements on a web page. For example, when a screen reader encounters an element with a specific ARIA role, it can convey to the user the type of control or region that element represents (like a "navigation" or "button"). This context is vital for helping users understand and navigate the web more effectively.

In contrast, visual enhancements do not directly contribute to accessibility for users relying on assistive technology. Restricting access does not align with the purpose of ARIA roles, which aim to improve accessibility rather than limit it. Lastly, while keyboard navigation is a fundamental principle of web accessibility, ARIA roles do not eliminate the need for it; rather, they complement keyboard navigation by providing additional context and support for users who may not be using a mouse.