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.
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((entry) => {
if (entry.isIntersecting) {
intersectingCount += 1;
} else {
intersectingCount -= 1;
}
});
}
To see a more concrete example, take a look at Handling intersection changes.