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IntersectionObserverEntry.isIntersecting

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.

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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 51 16 55
55
53 — 55
Disabled
Disabled 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.
No ? ?
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 51 51 No ? ? ? 5.0

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserverEntry/isIntersecting