DOM4を実装すると、ACID3がパスしなくなるらしい

ACID3が標準準拠テストだと思ってる人はまだいそうだけど、これは非常にいろいろな問題を持ってるテストで、これをパスしたからハッピーということではない。

で、最近一番面白いネタが、DOM4の現在の仕様だとこのテストはパスしなくなる。Jonasがwebappsのメーリングリストにこの話を投げてる。http://lists.w3.org/Archives/Public/public-webapps/2011JulSep/1329.html

The new DOM-Core specification changes some of the behavior for DocType nodes to make them act more like all other nodes in the DOM.
Specifically:

1. They always have a ownerDocument
   
2. They can move between, both using explicit calls to AdoptNode, and
   implicit adoption during for example insertBefore
   
3. They can be cloned between documents using importNode
   

We've written a patch to implement these changes in Gecko (which resulted in a nice reduction in code). However, ACID3 tests for the old behavior which is making it a harder decision to check this patch in. As I understand it this isn't a Gecko specific interaction with ACID3, but all browsers will see the same loss in ACID3 score if they implement the new DOM-Core spec.

で、ACID3自体がダメダメだから、直す話が実際あって、http://wiki.whatwg.org/wiki/Acid3にいろいろ書かれてる。