Footnotes present another challenge to reading enjoyment. Prior to EPUB 3, note references could not be easily distinguished from regular hyperlinks, and the notes themselves were typically marked up using paragraphs and divs, which impeded the ability to skip through them or past them entirely.
Picture yourself in a position where you might have to skip a note or two before you can continue reading after every paragraph. And having to manually listen to each new paragraph to determine if it’s a note or a continuation of the text. The practice of clumping all notes at the end of a section is slightly more helpful, but still interferes with the content flow however you read.
The epub:type attribute helps solve both these
problems when used with the new HTML aside
element, as in the following example:
<p>…<a epub:type="noteref" href="#n1">1</a> …</p>
<aside epub:type="footnote" id="n1">
…
</aside>
The “noteref” term in the epub:type attribute
identifies that the link points to a note, which allows a reading system to
alert the reader they’ve encountered a footnote reference. It also provides
the reader the ability to tell the reading system to ignore all such links
if she wants to read the text through uninterrupted. Don’t underestimate the
irritation factor of constant note links being announced!
Likewise, the aside element has also been
identified as a footnote, permitting the reading system to skip it if the
reader has chosen to turn off footnote playback. Putting the note in an
aside also indicates that the content is
not part of the main document flow.
But footnotes are often a nuisance for all readers; sighted readers typically care just as little to encounter them in the text. Identifying all your notes could also allow sighted readers to automatically hide them if they prefer them to not be rendered, saving sometimes limited screen space for the narrative prose. A configurable reading system that lets you decide what content you want to see is within reach with semantically meaningful data.
It might seem odd to talk about page numbering in a digital format guide, but ebooks have been used by students the world over for more than a decade to facilitate their learning in a world only just weaning itself off print. Picture yourself using an ebook in a classroom where print books are still used. When the professor instructs everyone to open their book to a specific page, your ebook will be most unhelpful if you can’t find the same location. Or think about trying to quote a passage from a novel in your final paper and not being able to indicate where in the print source it came from. Page numbers are not an antiquated concept quite yet.
The practice to date has been to include page numbers using anchor tags, as in the following example:
<a name="page361"/>
But unless a reading system does a heuristic inspection of the name attribute’s value to see if it starts with
“page” or “pg” or “p” there’s not going to be a lot of value to this kind of
tagging for readers. These kinds of anchor points did give a location for
navigating from the NCX page list, and it did keep the number from being
rendered, but it’s also lost data.
EPUB 3 once again calls on the epub:type
attribute to include better semantics:
<span id="page361" epub:type="pagenumber">361</span>
It’s now clearly stated what the span contains, and the page number no longer has to be extracted from an attribute and separated from a page identifier label. It’s now up to the reader and their reading system to determine when and how to render this information, if at all.
One note when you do include page numbering is to remember that you should also include the ISBN of the source it came from in the package metadata:
<dc:source>urn:isbn:9780375704024</dc:source>
Inclusion of the ISBN is recommended as it can be used to distinguish between hardcover and softcover versions, and between different editions, of the source book. All of these typically would have different pagination, which would affect the ability of the reader to accurately synchronize with the print source in use.
This will ensure that students, teachers, professors, and other interested parties can verify whether the digital edition matches the course criteria. Of course, the ideal day coming will be when everyone is using digital editions and sharing bookmarks—and maybe even auto-synchronizing with the professor’s edition.
But there are also other settings beyond educational where page number can be useful, too. Reading is also a social activity, and being able to reference by page numbers in leisure books allows for easier participation in reading groups, for example.
The world isn’t completely digital yet, so don’t dismiss out of hand the need for print-digital referencing when you’re producing both formats for a book.