nsHTMLCopyEncoder produces text/html encodings only for HTML documents, but it should do so for XHTML too. nsHTMLCopyEncoder::SetSelection checks nsIHTMLDocument.IsHTML, and if false (and it is false for XHTML), it treats the document as text and doesn't produce text/html: > // also consider ourselves in a text widget if we can't find an html document > nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(mDocument); > if (!(htmlDoc && mDocument->IsHTML())) { > mIsTextWidget = true; The IsHTML term seems to have been introduced in bug 270145; see bz's bug 270145 comment 5. (IsCaseSensitive apparently served the purpose that IsHTML serves now. Bug 487023 made the change.) I tried removing that term and then copying and pasting from an XHTML document, but when CDATA was present, its closing "]]>" was visible in the resulting paste. I don't know if there are other problems. Spun out from bug 723163. See Henri's comments there about how this is the wrong behavior: bug 723163 comment 13, bug 723163 comment 14, and bug 723163 comment 34.

Of course the problem is that some XHTML documents can't be serialized as text/html....

Are you saying the prospect of nsHTMLCopyEncoder producing text/html for XHTML is doomed from the get-go? Henri says, "In most normal cases, the text/html serializer can convert XHTML to HTML just fine." I'm new to how this works -- is there some other class that could (even lossily) translate XHTML to HTML, or could put application/xhtml+xml on the clipboard?

I think what Henri says doesn't contradict what I said... We can certainly produce text/html, and for most actual uses of XHTML it would work. In some cases it would produce something quite different from what we started with. Not necessarily even "lossy", but "different".

I guess the real question is whether we care about those cases. We may not.

Ah, bug 703514 comment 2, but apparently it broke some about:memory tests (bug 703514 comment 13). I still think we should drop that IsHTML() term :-)

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046 Move all DOM bugs that haven't been updated in more than 3 years and has no one currently assigned to P5. If you have questions, please contact :mdaly.