We fail a test here because of this: http://w3c-test.org/dom/nodes/Node-isEqualNode.xhtml Spec: https://dom.spec.whatwg.org/#concept-node-equals The original DOM 3 Core spec said to take internal subsets into account, unlike current DOM: http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-isEqualNode IE matches the old DOM 3 Core behavior, as do we. Chrome follows the new DOM spec. I don't know why the spec changed. Anne, Ms2ger, do you?
The specification has dropped internal subsets as a concept that you keep around for DocumentType objects. So they simply don't exist and therefore are not compared.
Created attachment 8672382 [details] [diff] [review] Patch Aha, thanks. We want to get rid of those anyway (bug 801545), so this makes sense. https://treeherder.mozilla.org/#/jobs?repo=try&revision=04f3231c1c8b
Comment on attachment 8672382 [details] [diff] [review] Patch r=me