Hyperlink to non-standard resource …

If you’ve seen this message from epubcheck, you know where this post is going.

It’s easy to get tripped up on EPUB’s web-like, but not quite web, quirks, as what is valid to do on in a web page isn’t always valid to do in an EPUB. Particularly when it comes to linking to resources, as you have to follow EPUB’s core media type requirements.

If epubcheck has spewed the “hyperlink to non-standard resource” message at you, it’s because you can only have internal links go to XHTML or SVG documents, at least without a fallback.

But don’t fret. There are some easy, and not-so-easy, workarounds to this problem, which is what I’m going to look at.

Continue Reading Hyperlink to non-standard resource …

Fallbacks, fallbacks, fallbacks

So how many fallback methods is too many fallback methods? Or is there such a thing?

EPUB 3 certainly has its share. There are fallbacks for items in the spine, content switching fallbacks at the markup level, element intrinsic fallbacks, manifest fallbacks for content elements, and even binding of media types to scripted fallbacks (before reaching intrinsic fallbacks!).

Sometimes the number of them is directed at compliance with EPUB 2 content, knowing that there would be a transition phase, but looking at each of the methods none is actually specific to backwards compatibility. And remove any of them and you lose some predictability of rendering.

This post isn’t going to be a how-to guide to fallbacks. You can read the details of each in the specs, and there’s an explanation of them in the best practices book. I’m instead going to look at the role fallbacks play and see what patterns arise.
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