Node: lookupPrefix() method's example now outputs null

[jasonren0403]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Node/lookupPrefix

What specific section or headline is this issue about?

Example

What information was incorrect, unhelpful, or incomplete?

whether in embed example or in playground, the output is null instead of what comment implied

What did you expect to see?

consistent comment and output

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

No response

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/api/node/lookupprefix
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/Node/lookupPrefix
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/node/lookupprefix/index.md
• Last commit: cac79d0
• Document last modified: 2025-06-06T03:11:11.000Z

[Josh-Cena]

I updated lookupNamespaceURI and isDefaultNamespace, but probably lookupPrefix has changed at some point as well

[Shrinivassab]

I think the code returns null because of the trailing spaces in the namespaces UTIs and incorrect namespace scope is relativeto the elements that being queried?

I tried few approach and made some update in the jsfiddle if this looks good, I can raise a PR or suggest if something i missed: jsFiddle