High contrast between text elements and the background on a web page is an example of which web accessibility principle?

High contrast between text elements and the background on a web page aligns with the perceivable principle of web accessibility. This principle emphasizes that information and user interface components must be presented in a way that users can perceive them. High contrast ensures that text is distinguishable from its background, making it easier for users, particularly those with visual impairments, to read and understand the content.

This principle is a critical component of accessibility guidelines, such as the Web Content Accessibility Guidelines (WCAG), which indicate that presenting text with sufficient contrast is essential to accommodate various users' needs, including those who may have color vision deficiencies or low vision. By adhering to the perceivable standard, developers help create more inclusive and usable web experiences.

The other principles of web accessibility focus on different aspects: understandable relates to ensuring content is clear and straightforward; operable refers to making sure that users can navigate and interact with the website; and robust deals with ensuring content can be reliably interpreted by a wide variety of user agents, including assistive technologies. While all principles contribute to a comprehensive approach to accessibility, contrasting text and background specifically embodies the principle of perceivability.