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.
A number between 0.0 and 1.0 which indicates how much of the target element is actually visible within the root's intersection rectangle. More precisely, this value is the ratio of the area of the intersection rectangle (intersectionRect
) to the area of the target's bounds rectangle (boundingClientRect
).
If the area of the target's bounds rectangle is zero, the returned value is 1 if isIntersecting
is true
or 0 if not.
In this simple example, an intersection callback sets each target element's opacity
to the intersection ratio of that element with the root.
js
function intersectionCallback(entries) { entries.forEach((entry) => { entry.target.style.opacity = entry.intersectionRatio; }); }
To see a more concrete example, take a look at Handling intersection changes.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
intersectionRatio |
51 | 15 | 55 | No | 38 | 12.1 | 51 | 51 | 55 | 41 | 12.2 | 5.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserverEntry/intersectionRatio