api.Window.sessionStorage - Firefox does not support sessionStorage on a duplicate tab

[DuxuanWu]

What type of issue is this?

Incorrect support data (example: BrowserX says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

It is indicated that Firefox has full support on sessionStorage, which means it should support "Duplicating a tab copies the tab's sessionStorage into the new tab.", but the sessionStorage is not copied over for a duplicate tab.

What browsers does this problem apply to, if applicable?

Firefox

What did you expect to see?

I expect sessionStorage copies over for a duplicate tab

Did you test this? If so, how?

Yes, I opened a tab in Firefox and created a duplicate tab, and I didn't see the sessionStorage content was copied over.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage

MDN metadata

MDN page report details

• Query: api.Window.sessionStorage
• Report started: 2025-01-16T20:56:41.852Z

[skyclouds2001]

see #21594, which fires the similar case in safari
and see mdn/content#30598 for similar case in chrome

after all, I think it is the behavior of the browser, not a bug

It is indicated that Firefox has full support on sessionStorage, which means it should support "Duplicating a tab copies the tab's sessionStorage into the new tab.", but the sessionStorage is not copied over for a duplicate tab.

also, I don't understand what is it should support "Duplicating a tab copies the tab's sessionStorage into the new tab."