I believe it’s a failing of HTML that it does not include a footnote tag. I’ve heard that earlier drafts did include it, but it was dropped for lack of interest. Clearly, early HTML users — math and comp. sci. types — weren’t as fond of footnotes as those in the humanities. Lawyers, for instance, are fanatical about footnotes. There are entire books on proper citation for legal documents.
It’s not valid XHTML to put a block-level element like P inside of a SPAN. So put the footnote in a DIV instead of a SPAN, I thought. No dice: you can’t put a DIV inside of a P. So in the end I have to put the footnote in a DIV entirely outside P that referenced it. I need some way to connect the footnote with the place in the text where it’s referenced, so at this point I might as well go back to internal links.
Perhaps I’m making this more complicated than it really is.