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.
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((entry) => {
refreshZones.push({
element: entry.target,
rect: entry.intersectionRect,
});
});
}