IntersectionObserver() constructor creates and returns a new
IntersectionObserver object. The
rootMargin, if specified, is checked to ensure it's syntactically correct, the thresholds are checked to ensure that they're all in the range 0.0 and 1.0 inclusive, and the threshold list is sorted in ascending numeric order. if the threshold list is empty, it's set to the array [0.0].
var observer = new IntersectionObserver(callback[, options]);
- A function which is called when the percentage of the target element is visible crosses a threshold. The callback receives as input two parameters:
- An optional object which customizes the observer. If
optionsisn't specified, the observer uses the document's viewport as the root, with no margin, and a 0% threshold (meaning that even a one-pixel change is enough to trigger a callback). You can provide any combination of the following options:
Elementobject which is an ancestor of the intended target, whose bounding rectangle will be considered the viewport. Any part of the target not visible in the visible area of the
rootis not considered visible.
- A string which specifies a set of offsets to add to the root's bounding_box when calculating intersections, effectively shrinking or growing the root for calculation purposes. The syntax is approximately the same as that for the CSS
marginproperty; see The root element and root margin in Intersection Observer API for more information on how the margin works and the syntax. The default is "0px 0px 0px 0px".
- Either a single number or an array of numbers between 0.0 and 1.0, specifying a ratio of intersection area to total bounding box area for the observed target. A value of 0.0 means that even a single visible pixel counts as the target being visible. 1.0 means that the entire target element is visible. See Thresholds in Intersection Observer API for a more in-depth description of how thresholds are used. The default is a threshold of 0.0.
IntersectionObserver which can be used to watch for the visibility of a target element within the specified
root crossing through any of the specified visibility
thresholds. Call its
observe() method to begin watching for the visibility changes on a given target.
- The specified
- One or more of the values in
thresholdis outside the range 0.0 to 1.0.
The definition of 'IntersectionObserver constructor' in that specification.
|Working Draft||Initial definition.|
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.
|Feature||Android webview||Chrome for Android||Edge mobile||Firefox for Android||Opera Android||iOS Safari||Samsung Internet|
1. From version 53 until version 55 (exclusive): this feature is behind the
dom.IntersectionObserver.enabled preference (needs to be set to
true). To change preferences in Firefox, visit about:config.