What about detached headings?

[domenic]

What is the level of document.createElement("html5-h")? What about if I put one in via the parser, but then remove it later?

[matatk]

So far we've been concentrating on the perspective of someone writing the HTML directly; the next stage being to move on to things like #25 and #26, where an element that was already declared in the HTML is moved.

I'm not actually sure what the answer to your question is yet -- there may well be an error thrown when trying to create it "just like that" -- but I would hope that, if that sort of thing were to be gracefully handled when the element is instantiated, then the solution adopted for #25 and #26 should take care of the rest.

[domenic]

I think the best answer would be null for document.createElement("html5-h").level, and "" for document.createElement("html5-h").getAttribute("level").