98439 2012-10-04 12:49:33 -0700 MutationRecord oldValue should be null when *OldValue is false 2012-10-04 14:19:05 -0700 1 1 1 Unclassified WebKit DOM 528+ (Nightly build) Unspecified Unspecified RESOLVED WORKSFORME http://dom.spec.whatwg.org/#mutationrecord P2 Normal --- 1 arv webkit-unassigned adamk rafaelw oldest_to_newest 734935 0 arv 2012-10-04 12:49:33 -0700 For {characterData: true} oldValue should be null and not '' var text = document.createTextNode('abc'); var observer = new WebKitMutationObserver(function() {}); observer.observe(text, { characterData: true }); text.data = 'def'; var records = observer.takeRecords(); shouldBeNull('records[0].attributeName') 735005 1 adamk 2012-10-04 14:19:05 -0700 I can't reproduce this problem. Your test case doesn't actually test oldValue; I think if you do, you'll find it is null (as oldValue is already properly annotated in MutationRecord.idl).