css.properties.break-after / css.properties.break-before - "avoid" / "avoid-page" is not supported in Firefox

[n1kPLV]

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?

The compat data claims that break-before: avoid and/or break-after: avoid works in Firefox from Version 72 on. This is incorrect, as these are still not implemented.

What browsers does this problem apply to, if applicable?

Firefox

What did you expect to see?

Firefox not supporting this property

Did you test this? If so, how?

I constructed a web page such that a page break will occur after a block, in this case a h2, and included a css style with

h2 {
        break-after: avoid;
} 

I opened this page in firefox 123, opened the "printing" dialog and verified in the print preview that a page break was inserted after the h2 element.

I then also tested with

h2 + * {
        break-before: avoid;
} 

which also didn't prevent the page break between the h2 and the following page element.

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

There is an open firefox bug related to implementing this feature from 12 years ago: https://bugzilla.mozilla.org/show_bug.cgi?id=775617

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/break-after

MDN metadata

MDN page report details

• Query: css.properties.break-after
• Report started: 2024-03-27T13:27:11.183Z