coderef

Layout instability performance entriesLimited availability

A layout-shift performance entry measures the layout stability of web pages based on movements of the elements on the page. They're used to calculate cumulative layout shift (CLS), a common metric for perceived stability.

Not yet supported in all major browsers — check the table and provide a fallback.

How to use ↓Compare browsers

Browser support

DesktopChrome
1–83Not supported
84+Supportedsince Jul 27, 2020
Current: 155
Edge
12–83Not supported
84+Supportedsince Jul 16, 2020
Current: 154
Firefox
✕Not supportedup to 157
Current: 157
Safari
✕Not supportedup to 27
Current: 27
MobileChrome Android
18–83Not supported
84+Supportedsince Jul 27, 2020
Current: 155
Firefox Android
✕Not supportedup to 157
Current: 157
Safari iOS
✕Not supportedup to 27
Current: 27

How to use

Not supported in Firefox, Safari, Firefox Android, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.

Example

Full syntax and examples are on MDN: LayoutShift.

Feature detection

JS · check before using
if ("LayoutShift" in globalThis) {
  // LayoutShift is available
} else {
  // load a polyfill or use a fallback
}

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (11). The overall table above shows when the whole feature works.

Sub-featureChromeEdgeFirefoxSafariChrome AndroidFirefox AndroidSafari iOS
LayoutShift7779✕✕77✕✕
LayoutShift.hadRecentInput7779✕✕77✕✕
LayoutShift.lastInputTime7779✕✕77✕✕
LayoutShift.sources8484✕✕84✕✕
LayoutShift.toJSON7779✕✕77✕✕
LayoutShift.value7779✕✕77✕✕
LayoutShiftAttribution8484✕✕84✕✕
LayoutShiftAttribution.currentRect8484✕✕84✕✕
LayoutShiftAttribution.node8484✕✕84✕✕
LayoutShiftAttribution.previousRect8484✕✕84✕✕
LayoutShiftAttribution.toJSON8484✕✕84✕✕