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

The IntersectionObserverEntry interface's read-only intersectionRect property is a DOMRectReadOnly object which describes the smallest rectangle that contains the entire portion of the target element which is currently visible within the intersection root.


var intersectionRect = IntersectionObserverEntry.intersectionRect;


A DOMRectReadOnly which describes the part of the target element that's currently visible within the root's intersection rectangle.

This rectangle is computed by taking the intersection of boundingClientRect with each of the target's ancestors' clip rectangles, with the exception of the intersection root itself.


In this simple example, an intersection callback stores the intersection rectangle for later use by the code that draws the target elements' contents, so that only the visible area is redrawn.

function intersectionCallback(entries) {
  entries.forEach(function(entry) {
      rect: entry.intersectionRect


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

Browser compatibility

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