Create an affixing header that behaves normally as a user navigates down a page, but reveals itself naturally when a user scrolls or drags upwards. Inspired by iOS Safari, Medium, and others. See an example implementation to see what it’s about. Works on desktop and mobile browsers.
The module is ESM-only and exports a single default affixingHeader function:
The DOM element to which the affixing behavior should be attached. Must be a single HTMLElement (e.g., the result of document.querySelector or document.getElementById), not a NodeList.
The affixingHeader function returns a cleanup function that takes no arguments and is used to remove listeners and cleanup the affixing behavior.
This package uses onscrolling, a requestAnimationFrame-based, performant, mobile-friendly scroll event handler, to listen for page scrolls, but has no other dependencies.
The scroll handling uses requestAnimationFrame, which is only available in IE10+. To add full support for older browsers, just include a requestAnimationFrame polyfill.