I\'ve heard that putting a block element inside a inline element is a HTML sin:
What we have here is a
There's a DTD for HTML 4 at http://www.w3.org/TR/REC-html40/sgml/dtd.html . This DTD is the machine-processable form of the spec, with the limitation that a DTD governs XML and HTML 4, especially the "transient" flavor, permits a lot of things that are not "legal" XML. Still, I consider it comes close to codifying the intent of the specifiers.
I would interpret the tags listed in this hierarchy to be the total of tags allowed.
While the spec may say "inline elements," I'm pretty sure it's not intended that you can get around the intent by declaring the display type of a block element to be inline. Inline tags have different semantics no matter how you may abuse them.
On the other hand, I find it intriguing that the inclusion of special
seems to allow nesting A
elements. There's probably some strong wording in the spec that disallows this even if it's XML-syntactically correct but I won't pursue this further as it's not the topic of the question.