This Introduction to the Navigation File of an EPUB breaks down the elements that make up this important file.
Subject(s):
Ebook Production
Resource Type(s):
Checklist, Foundations and Rationale, Standards and Best Practices
Audience:
Technical
Before reading this, you might want to read:
The navigation file or navigation document—which is almost always called either nav.xhtml or toc.xhtml in EPUB 3—is an XHTML file that offers a few different ways of navigating a book. It usually contains a table of contents (that is different from the textual table of contents – the contents page that appears in the book), a set of landmarks, and sometimes a page list. Reading systems and software use the navigation file to create the list of links that are usually accessed through a sidebar or top menu.
When you have a navigation file that is as robust as possible, it ensures that all readers will be able to quickly and easily navigate the book.
The table of contents shows the complete list of the headings of the book, and uses a nested list, like:
The landmarks section links to major points of the book’s contents, like the Cover, Front matter, Start of Reading, and Back matter. It does not link to individual parts, chapters, or subsections. When you export from InDesign, the EPUB always has one landmark: to the Cover of the book. This is a great start, but you are encouraged to add more! The page list will link to all the pages of the book. This is a super helpful method of navigation, and is highly recommended! In order to make a page list, you first have to add page breaks to the book – see the InDesign to EPUB category for help on that!
Download a PDF checklist for a great navigation file.