A better, smoother, more performant onscroll event interface based on the concepts from this html5rocks tutorial. It uses
requestAnimationFrame plus debouncing for performance and mobile-compatibility (thanks to the
touchmove event), giving you a fighting chance to achieve the hallowed 60fps of lore with your scroll-listening UI.
The module exports an
onscrolling module if being used with a CommonJS or AMD module loader, or else exposes a global object as
The function to call on a scroll event. In this default version, the module will only call the
callback() when the page has been scrolled vertically. It will be passed the current vertical scroll position to the callback.
The scroll axis to monitor. Values can be
horizontal to trigger when the page is scrolled horizontally,
vertical to trigger when the page is scrolled vertically (the default behavior if not direction is provided), or
any to trigger when the page is scrolled in any direction.
The function to call when the page is scrolled. It will be passed the current scroll position as a number if listening to a single scroll direction, or an array
[x,y] if callback is listening for
any scroll direction change.
The function to remove from the onscroll handler. In this default version, the function will be removed from the vertical scroll queue.
The scroll axis that
fn was listening for. Can be
any to match how the function was originally attached. If a function was attached to multiple scroll directions, calling this method for a specific direction will only remove the listener for that direction.
The function to remove from the onscroll handler for the specified direction.
Out of the box, onscrolling uses
requestAnimationFrame, which is only available in IE10+. For older browsers, your scroll watchers simply won’t run. To add compatibility for those browsers, just include a requestAnimationFrame polyfill.
Tests use Mocha + Should.js + Sinon. Using
npm test will run the tests in headless Chrome via mocha-chrome, but you can also open
test/index.html directly in a browser.
- Add optional param to specify an object other than
windowto monitor for scroll events
mutatefunctions to attach handlers specifically to the measuring (read) or mutating (write) portion of each cycle to minimize layout calculations
Note: This package was formerly known as jank-free-onscroll