The scroll event fires when the document view or an element has been scrolled.

Bubbles Not on elements, but bubbles to the default view when fired on the document
Cancelable No
Interface Event
Event handler property onscroll

 

Note: In iOS UIWebViews, scroll events are not fired while scrolling is taking place; they are only fired after the scrolling has completed. See Bootstrap issue #16202. Safari and WKWebViews are not affected by this bug.

Examples

Scroll event throttling

Since scroll events can fire at a high rate, the event handler shouldn't execute computationally expensive operations such as DOM modifications. Instead, it is recommended to throttle the event using requestAnimationFrame(), setTimeout(), or a CustomEvent, as follows.

Note, however, that input events and animation frames are fired at about the same rate, and therefore the optimization below is often unnecessary. This example optimizes thescroll event for requestAnimationFrame.

// Reference: http://www.html5rocks.com/en/tutorials/speed/animations/

let last_known_scroll_position = 0;
let ticking = false;

function doSomething(scroll_pos) {
  // Do something with the scroll position
}

window.addEventListener('scroll', function(e) {
  last_known_scroll_position = window.scrollY;

  if (!ticking) {
    window.requestAnimationFrame(function() {
      doSomething(last_known_scroll_position);
      ticking = false;
    });

    ticking = true;
  }
});

See more, similar examples on the resize event page.

Specifications

Specification Status
Document Object Model (DOM) Level 3 Events Specification Obsolete

Browser compatibility

No compatibility data found. Please contribute data for "api.Document.scroll" (depth: 1) to the MDN compatibility data repository.

See also

Document Tags and Contributors

Last updated by: irenesmith,