Baseline 2024
Newly available
The ContentVisibilityAutoStateChangeEvent
interface is the event object for the contentvisibilityautostatechange
event, which fires on any element with content-visibility: auto
set on it when it starts or stops being relevant to the user and skipping its contents.
While the element is not relevant (between the start and end events), the user agent skips an element's rendering, including layout and painting. This can significantly improve page rendering speed. The contentvisibilityautostatechange
event provides a way for an app's code to also start or stop rendering processes (e.g., drawing on a <canvas>
) when they are not needed, thereby conserving processing power.
Note that even when hidden from view, element contents will remain semantically relevant (e.g., to assistive technology users), so this signal should not be used to skip significant semantic DOM updates.
Event ContentVisibilityAutoStateChangeEvent ConstructorContentVisibilityAutoStateChangeEvent()
Creates a new ContentVisibilityAutoStateChangeEvent
object instance.
Inherits properties from its parent, Event
.
skipped
Read only
Returns true
if the user agent is skipping the element's rendering, or false
otherwise.
const canvasElem = document.querySelector("canvas");
canvasElem.addEventListener("contentvisibilityautostatechange", stateChanged);
canvasElem.style.contentVisibility = "auto";
function stateChanged(event) {
if (event.skipped) {
stopCanvasUpdates(canvasElem);
} else {
startCanvasUpdates(canvasElem);
}
}
// Call this when the canvas updates need to start.
function startCanvasUpdates(canvas) {
// â¦
}
// Call this when the canvas updates need to stop.
function stopCanvasUpdates(canvas) {
// â¦
}
Specifications Browser compatibility See also
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HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4