What principle ensures that users can interact with a website regardless of the device they are using?

The principle that ensures users can interact with a website regardless of the device they are using is Robust. This principle emphasizes the importance of creating content that can be reliably interpreted by a wide variety of user agents, including various browsers and assistive technologies. By adhering to web standards and best practices, developers ensure that their content remains accessible not just now, but also as technologies evolve, allowing users to access and interact with the website effectively, no matter which device they are on.

Robustness encompasses considerations such as properly structured HTML, valid coding practices, and semantic markup, all of which contribute to creating a stable and adaptable experience for users, whether they are using a desktop, tablet, or mobile device. This principle is critical in enabling accessibility across different platforms and ensuring that the website can accommodate future innovations in technology. In contrast, while the other principles—operable, perceivable, and understandable—are essential for creating an inclusive user experience, they do not specifically address the need for adaptability and interoperability across different devices.