IntersectionObserver
interface's read-only
root
property identifies the
元素
or
Document
whose bounds are treated as the
bounding box
的
viewport
for the element which is the observer's target.
若
root
is
null
, then the bounds of the actual document viewport are used.
var root = intersectionObserver.root;
A
元素
or
Document
object whose bounding box is used as the bounds of the viewport for the purposes of determining how much of the target element is visible. The intersection of this bounding rectangle, offset by any margins specified in the options passed to the
IntersectionObserver()
constructor, the target element's bounds, minus the bounds of every element or other object which overlaps the target element, is considered to be the visible area of the target element.
若
root
is
null
, then the owning document is used as the root, and the bounds its viewport (that is, the visible area of the document) are used as the root bounds.
This example sets the
border
of the intersection observer's root element to be a 2-pixel medium green line.
observer.root.style.border = "2px solid #44aa44";
| 规范 | 状态 | 注释 |
|---|---|---|
|
Intersection Observer
The definition of 'IntersectionObserver' in that specification. |
工作草案 | 初始定义 |
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.
更新 GitHub 上的兼容性数据| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
root
|
Chrome 51 | Edge 15 |
Firefox
55
|
IE No | Opera Yes | Safari 12.1 | WebView Android 51 | Chrome Android 51 | Firefox Android ? | Opera Android ? | Safari iOS 12.2 | Samsung Internet Android 5.0 |
完整支持
不支持
兼容性未知
实验。期望将来行为有所改变。
用户必须明确启用此特征。
IntersectionObserver
root
rootMargin
thresholds