MutationObserver attribute filter ignores attributes with a namespace

[josepharhar]

What is the issue with the DOM Standard?

When the attributesFilter property is used for a MutationObserver, attributes with namespaces are unconditionally excluded from getting mutation records:

https://dom.spec.whatwg.org/#queueing-a-mutation-record

type is "attributes", options["attributeFilter"] exists, and options["attributeFilter"] does not contain name or namespace is non-null

I don't know any of the history here, but this capability was asked for here: https://issues.chromium.org/issues/392661412

[annevk]

This is by design. We'd have to extend attributeFilter to also support namespaced attributes. For however long this feature has existed there have been no requests for that, but it's certainly possible to add.