coderef

Back/forward cache blocking reasonsLimited availability

The notRestoredReasons property of a PerformanceNavigationTiming object explains why the current document was blocked from using the back/forward cache (also known as the bfcache) on navigation.

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

How to use ↓Compare browsers

Browser support

DesktopChrome
1–124Not supported
125+Supportedsince May 14, 2024
Current: 155
Edge
12–124Not supported
125+Supportedsince May 17, 2024
Current: 154
Firefox
✕Not supportedup to 157
Current: 157
Safari
✕Not supportedup to 27
Current: 27
MobileChrome Android
18–124Not supported
125+Supportedsince May 14, 2024
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: NotRestoredReasonDetails.

Feature detection

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

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (12). The overall table above shows when the whole feature works.

Sub-featureChromeEdgeFirefoxSafariChrome AndroidFirefox AndroidSafari iOS
NotRestoredReasonDetails125125✕✕125✕✕
NotRestoredReasonDetails.reason125125✕✕125✕✕
NotRestoredReasonDetails.toJSON125125✕✕125✕✕
NotRestoredReasons125125✕✕125✕✕
NotRestoredReasons.children125125✕✕125✕✕
NotRestoredReasons.id125125✕✕125✕✕
NotRestoredReasons.name125125✕✕125✕✕
NotRestoredReasons.reasons125125✕✕125✕✕
NotRestoredReasons.src125125✕✕125✕✕
NotRestoredReasons.toJSON125125✕✕125✕✕
NotRestoredReasons.url125125✕✕125✕✕
PerformanceNavigationTiming.notRestoredReasons125125✕✕125✕✕