Originally Posted by RAH
I agree that the "pages left in chapter" is very handy. I believe that a "chapter" is considered to be anything that is implemented in the epub as an H1 entry (in html terms). Such entries are also included in the Table of Contents. Sub-entries are implemented as H2, H3, etc. HTML tags. So, if the Nook uses the H1 entry as its mechanism to determine how many pages are left in a chapter, it will screw up if your epub has real chapters at a lower level (h2, etc) in that hierarchy.
You could reformat the pub with Sigil and change the real chapters to use H1 as the tag, but you'd have to remove that tag from the higher-levels (books). You could, I suppose, build your own links to those higher areas.
I am unsure about whether current Nooks show sub-entries in the Table of Contents. With the Classic Nook, they did for awhile, then they lost the ability, then I think I read that they have reacquired it. Keeps changing.
By the way, what does "ncx" stand for?
NCX (Navigation Control file for XML) is the table of contents file for an epub. Most modern epub readers don't need an in-line toc even though they usually come with one. You know when you're scrolling through the book and you come across a page or pages that say "Table of Contents"? That is an inline toc. It's basically built just like any other page or chapter in the book. This is what mobi uses and it's a hold-over from the early days of ebooks. The ncx file, usually named toc.ncx, is the table of contents file and it's what you see on the NT when you bring up the menu and click on content. Epubs on most modern readers really only need the toc.ncx file and don't need the hand-built, in-line toc.
As far as the H1 tags go, I don't think that's what drives the chapters. When I look at the structure of the epub in question, every single chapter or section of the book is named with H1 tag. That's all they used. The multi-level structure, the hieratchy is established in the toc.ncx file, so there's nothing to change as all the heading tags are all already H1.
The Nook Tablet, and I believe the Nook Color show all levels of a properly built chapter hierarchy. I'm not certain about older Nooks but I'm not concerned with them either. The NT is the only one I'm concerned with.