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This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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.


var isIntersecting = IntersectionObserverEntry.isIntersecting;


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).


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.


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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support51 No


53 — 551

No ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support5151 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,