This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
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.
Syntax
var intersectionRatio =
IntersectionObserverEntry.intersectionRatio;
Value
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.
Example
In this simple example, an intersection callback sets each target element's opacity
to the intersection ratio of that element with the root.
function intersectionCallback(entries) { entries.forEach(function(entry) { entry.target.style.opacity = entry.intersectionRatio; }); }
To see a more concrete example, take a look at Handling intersection changes in Timing element visibility with the Intersection Observer API.
Specifications
Specification | Status | Comment |
---|---|---|
Intersection Observer The definition of 'IntersectionObserverEntry.intersectionratio' in that specification. |
Working Draft | Initial definition |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
intersectionRatio | Chrome Full support 51 | Edge Full support 15 | Firefox
Full support
55
| IE No support No | Opera Full support Yes | Safari ? | WebView Android Full support 51 | Chrome Android Full support 51 | Firefox Android ? | Opera Android ? | Safari iOS ? | Samsung Internet Android Full support 5.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
- User must explicitly enable this feature.
- User must explicitly enable this feature.