LayoutShiftAttribution

The LayoutShiftAttribution interface of the Layout Instability API provides debugging information about elements which have shifted.

Instances of LayoutShiftAttribution are returned in an array by calling LayoutShift.sources.

Properties

LayoutShiftAttribution.NodeRead only: Returns the element that has shifted (null if it has been removed).
LayoutShiftAttribution.previousRectRead only: Returns a DOMRectReadOnly object representing the position of the element before the shift.
LayoutShiftAttribution.currentRectRead only: Returns a DOMRectReadOnly object representing the position of the element after the shift.

Methods

LayoutShiftAttribution.toJSON(): Returns a JSON representation of the LayoutShiftAttribution object.

Examples

The following example finds the element that is causing the largest layout shift, and prints that node to the console. For more detail on this see Debug Web Vitals in the field.

function getCLSDebugTarget(entries) {
  const largestEntry = entries.reduce((a, b) => {
    return a && a.value > b.value ? a : b;
  });
  if (largestEntry && largestEntry.sources && largestEntry.sources.length) {
    const largestSource = largestEntry.sources.reduce((a, b) => {
      return a.node && a.previousRect.width * a.previousRect.height >
          b.previousRect.width * b.previousRect.height ? a : b;
    });
    if (largestSource) {
      return largestSource.node;
    }
  }
}

Specifications

Specification
Layout Instability # sec-layout-shift-attribution

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`LayoutShiftAttribution`	77	80	No	No	Yes	No	77	77	No	Yes	No	12.0
`currentRect`	77	80	No	No	Yes	No	77	77	No	Yes	No	12.0
`node`	77	80	No	No	Yes	No	77	77	No	Yes	No	12.0
`previousRect`	77	80	No	No	Yes	No	77	77	No	Yes	No	12.0
`toJSON`	77	80	No	No	Yes	No	77	77	No	Yes	No	12.0