NotRestoredReasons

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The NotRestoredReasons interface of the Performance 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 the PerformanceNavigationTiming.notRestoredReasons property.

Instance properties

children Read only Experimental: An array of NotRestoredReasons objects, 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>, children will return null.
id Read only Experimental: A string representing the id attribute value of the <iframe> the document is contained in (for example <iframe id="foo" src="...">). If the document is not in an <iframe> or the <iframe> has no id set, id will return null.
name Read only Experimental: A string representing the name attribute 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 no name set, name will return null.
reasons Read only Experimental: An array of NotRestoredReasonDetails objects, each representing a reason why the navigated page was blocked from using the bfcache. If the document is in a cross-origin <iframe>, reasons will return null, but the parent document may show a reason of "masked" if any <iframe>s blocked bfcache usage for the top-level frame.
src Read only Experimental: A 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>, src will return null.
url Read only Experimental: A string representing the URL of the navigated page or <iframe>. If the document is in a cross-origin <iframe>, url will return null.