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

The IntersectionObserver method observe() adds an element to the set of target elements being watched by the IntersectionObserver. One observer has one set of thresholds and one root, but can watch multiple target elements for visibility changes in keeping with those. To stop observing the element, call IntersectionObserver.unobserve().

When the visibility of the specified element crosses over one of the observer's visibility thresholds (as listed in IntersectionObserver.thresholds, the observer's callback is executed with an IntersectionObserverEntry representing the intersection change which occurred. Note that this design allows multiple elements' intersection changes to be processed by a single call to the callback using an array of IntersectionObserverEntry objects.





An element whose visibility within the root is to be monitored. This element must be a descendant of the root element (or contained wtihin the current document, if the root is the document's viewport).

Return value





Specification Status Comment
Intersection Observer
The definition of 'IntersectionObserver.observe()' in that specification.
Working Draft Initial definition.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support5115


53 — 551

No ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support5151 Yes ? ? ?5.0

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.

See also

Document Tags and Contributors

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