Document: scroll event

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

Bubbles Yes
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

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
scroll eventChrome Full support 1Edge Full support 12Firefox Full support 6IE Full support 9Opera Full support 11.6Safari Full support 2WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 6Opera Android Full support 12Safari iOS Full support 1Samsung Internet Android Full support 1.0

Legend

Full support  
Full support

See also