Highlightable

Highlightable is an adjective describing content or interface elements that can be emphasized visually by applying a highlight. In user interfaces, highlightable elements may respond to user actions such as hover, focus, selection, or explicit commands to mark them for attention. Highlighting typically changes visual properties such as background color, border, or text color to distinguish the item from its surroundings without altering the underlying content.

In web and application design, developers designate highlightable items using styling rules or scripting, often through CSS classes or attributes. Examples include search results that highlight matching terms, code editors that apply syntax highlighting, and note-taking tools that allow users to attach or remove highlight annotations. Accessibility considerations require sufficient contrast and, where possible, non-color cues (such as icons or underlines) to ensure highlights are perceivable by users with visual impairments.

Highlighting is distinct from selection or emphasis: highlighting is an annotation that persists as a visual cue, while selection is an interaction state usually tied to input focus or copy operations. Highlights can be ephemeral (for example, a transient hover) or persistent (for example, saved annotations). When implementing highlights, developers should consider performance and memory usage for large documents, and may use persistence mechanisms to store highlight metadata separately from content.

See also: syntax highlighting, text highlighting, annotation.