Example for CSSStyleDeclaration/setProperty doesn't work

[Dakotys]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleDeclaration/setProperty#result

What specific section or headline is this issue about?

Example in Result part

What information was incorrect, unhelpful, or incomplete?

Example throws error:

It used to work on on edge: chromium 129.0.2792.65:

I am not sure whether the issue is related to iframes or something else, but the example doesn't work.

PS: Console error differs across browsers, firefox throws TypeError: stylesheet is undefined; while Chromium throws TypeError: Cannot read properties of undefined (reading 'cssRules')

What did you expect to see?

Working example, or none at all.

Do you have any supporting links, references, or citations?

No response

Do you have anything more you want to share?

No response

[hamishwillee]

Thanks for reporting. This should be fixed by #37285. The code would be correct if the example was rendered in place, but it is imported into a frame, so the CSS of interest is the 0th indexed one.