addsticky

Addsticky is a term used in web development to describe a helper function or utility that applies and manages sticky behavior for an element as the page is scrolled. It is not a standardized API, but a pattern found in various libraries and projects where developers seek a simple way to keep a component visible without writing repetitive scroll logic.

Typically, an addsticky utility combines CSS sticky positioning with optional JavaScript logic. It may apply the CSS property position: sticky and top, or it may implement a scroll listener or an IntersectionObserver to toggle a sticky state, add a sticky class, or adjust inline styles when a threshold is reached.

Commonly, the API accepts an element and an options object. Options may include top or offset distance, z-index, a scrolling boundary, and optional callbacks for when the element becomes sticky or stops being sticky. Some implementations return a cleanup or destroy function to remove the behavior.

Usage usually involves selecting the target element and invoking addsticky with the desired settings. Depending on the library, behavior can be pure CSS, a JavaScript fallback for browsers without full support, or a combination of both to handle dynamic content and layout changes.

Compatibility and limitations: while position: sticky is broadly supported in modern browsers, practical guarantees depend on ancestor containers, overflow settings, and layout. Complex layouts or nested scrolling regions may require additional handling to ensure consistent behavior.

See also: sticky positioning, IntersectionObserver, scroll event handling.