LayoutShiftAttribution
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The LayoutShiftAttribution
interface provides debugging information about elements which have shifted.
Instances of LayoutShiftAttribution
are returned in an array by calling LayoutShift.sources
.
Instance properties
LayoutShiftAttribution.node
Read only Experimental-
Returns the element that has shifted (null if it has been removed).
LayoutShiftAttribution.previousRect
Read only Experimental-
Returns a
DOMRectReadOnly
object representing the position of the element before the shift. LayoutShiftAttribution.currentRect
Read only Experimental-
Returns a
DOMRectReadOnly
object representing the position of the element after the shift.
Instance methods
LayoutShiftAttribution.toJSON()
Experimental-
Returns a JSON representation of the
LayoutShiftAttribution
object.
Examples
The following example finds the element with the highest layout shift score, and returns the element in that entry with the largest size prior to the shift (previousRect
). For more detail on this see Debug Web Vitals in the field.
js
function getCLSDebugTarget(entries) {
const largestEntry = entries.reduce((a, b) =>
a && a.value > b.value ? a : b
);
if (largestEntry?.sources?.length) {
const largestSource = largestEntry.sources.reduce((a, b) => {
const area = (el) => el.previousRect.width * el.previousRect.height;
return a.node && area(a) > area(b) ? a : b;
});
if (largestSource) {
return largestSource.node;
}
}
}
Specifications
Specification |
---|
Layout Instability # sec-layout-shift-attribution |
Browser compatibility
BCD tables only load in the browser