MDN’s new design is in Beta! A sneak peek: https://blog.mozilla.org/opendesign/mdns-new-design-beta/

IntersectionObserverEntry.isIntersecting

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The IntersectionObserverEntry interface's read-only isIntersecting property is a Boolean value which is true if the target element intersects with the intersection observer's root. If this is true, then, the IntersectionObserverEntry describes a transition into a state of intersection; if it's false, then you know the transition is from intersecting to not-intersecting.

Syntax

var isIntersecting = IntersectionObserverEntry.isIntersecting;

Value

A Boolean value which indicates whether the target element has transitioned into a state of intersection (true) or out of a state of intersection (false).

Example

In this simple example, an intersection callback is used to update a counter of how many targeted elements are currently intersecting with the intersection root.

function intersectionCallback(entries) {
  entries.forEach(function(entry) {
    if (entry.isIntersecting) {
      intersectingCount += 1;
    } else {
      intersectingCount -= 1;
    }
  });
}

To see a more concrete example, take a look at "Handling intersection changes" in Timing element visibility with the Intersection Observer API.

Specifications

Specification Status Comment
Intersection Observer
The definition of 'IntersectionObserverEntry.isIntersecting' in that specification.
Editor's Draft Initial definition

Browser compatibility

FeatureChromeFirefoxEdgeInternet ExplorerOperaSafari
Basic Support51

53 — 551

55

15(No)??
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support5151(Yes)?(No)??

1. From version 53 until version 55 (exclusive): this feature is behind the dom.IntersectionObserver.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Document Tags and Contributors

 Contributors to this page: fscholz, Sheppy
 Last updated by: fscholz,