WAI-ARIA, which stands for Web Accessibility Initiative – Accessible Rich Internet Applications, is a specification developed by the W3C to enhance the accessibility of dynamic web content and user interface components. Its primary goal is to provide additional information to assistive technologies, such as screen readers, about elements and behaviors that are not natively accessible through standard HTML. This is especially important for interactive widgets, custom controls, and content that changes dynamically without a full page reload.

You should use WAI-ARIA when native HTML elements and attributes do not provide the necessary semantics or accessibility information for your web applications. For example, if you build a custom menu or tab interface using generic elements like div or span, screen readers may not recognize their roles or states. WAI-ARIA allows you to explicitly define roles, properties, and states, making your content more understandable and navigable for users relying on assistive technology.

However, it is important to remember that WAI-ARIA is not a replacement for semantic HTML. Always use native HTML elements such as button, nav, and ul whenever possible, as they come with built-in accessibility features. Only use ARIA attributes when there is no suitable native option, or when enhancing the accessibility of complex, custom components.

To illustrate the impact of WAI-ARIA, consider a dynamic menu component. Without ARIA, a screen reader may not announce the menu structure or the expanded and collapsed states of menu items. By adding appropriate ARIA roles and attributes, you can ensure that the menu is fully accessible.