intersectionRatio
The IntersectionObserverEntry interface's read-only intersectionRatio property tells you how much of the target element is currently visible within the root's intersection ratio, as a value between 0.0 and 1.0.
The IntersectionObserverEntry interface's read-only intersectionRatio property tells you how much of the target element is currently visible within the root's intersection ratio, as a value between 0.0 and 1.0.