NotRestoredReasons
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental:This is anexperimental technology
Check theBrowser compatibility table carefully before using this in production.
TheNotRestoredReasons interface of thePerformance API provides report data containing reasons why the current document was blocked from using the back/forward cache (bfcache) on navigation.
These objects are accessed via thePerformanceNavigationTiming.notRestoredReasons property.
Instance properties
childrenRead onlyExperimentalAn array of
NotRestoredReasonsobjects, one for each child<iframe>embedded in the current document, which may contain reasons why the top-level frame was blocked relating to the child frames. Each object has the same structure as the parent object — this way, any number of levels of embedded<iframe>s can be represented inside the object recursively. If the frame has no children, the array will be empty; if the document is in a cross-origin<iframe>,childrenwill returnnull.idRead onlyExperimentalA string representing the
idattribute value of the<iframe>the document is contained in (for example<iframe src="...">). If the document is not in an<iframe>or the<iframe>has noidset,idwill returnnull.nameRead onlyExperimentalA string representing the
nameattribute value of the<iframe>the document is contained in (for example<iframe name="bar" src="...">). If the document is not in an<iframe>or the<iframe>has nonameset,namewill returnnull.reasonsRead onlyExperimentalAn array of
NotRestoredReasonDetailsobjects, each representing a reason why the navigated page was blocked from using the bfcache. If the document is in a cross-origin<iframe>,reasonswill returnnull, but the parent document may show areasonof"masked"if any<iframe>s blocked bfcache usage for the top-level frame.srcRead onlyExperimentalA string representing the path to the source of the
<iframe>the document is contained in (for example<iframe src="exampleframe.html">). If the document is not in an<iframe>,srcwill returnnull.urlRead onlyExperimentalA string representing the URL of the navigated page or
<iframe>. If the document is in a cross-origin<iframe>,urlwill returnnull.
Instance methods
toJSON()ExperimentalAserializer; returns a JSON representation of the
NotRestoredReasonsobject.
Examples
SeeMonitoring bfcache blocking reasons for examples.
Specifications
| Specification |
|---|
| HTML # notrestoredreasons |