Document.createAttribute() should take in a localName, not a qualifiedName: - https://dom.spec.whatwg.org/#dom-document-createattribute Out behavior does not match the DOM specification or other browser engines.
Created attachment 386718 [details] Patch
Created attachment 386727 [details] WIP Patch
Comment on attachment 386718 [details] Patch Clearing flags on attachment: 386718 Committed r254021: <https://trac.webkit.org/changeset/254021>
All reviewed patches have been landed. Closing bug.
<rdar://problem/58309902>