Events - IntersectionObserver
This page tests the IntersectionObserver with an undefined root. The root is now
the viewport. But WHICH viewport?
- Desktop: decrease window height until the test element is below the fold. The observer should fire.
- Scroll until you see the test element.
- Mobile: zoom in, scroll down all the way, then scroll up. You’ll see a few intersections
observed even though the test element is not visible. That proves that the layout viewport is the
root, while it should be the visual viewport.
- Edge: make the browser window very narrow vertically. At a certain point the observer will fire, even though the target element never comes into view or moves out of it.
The observer should fire when this element is 50 % and 100% within the viewport.