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ElMiko · 03-25-2025, 09:12 AM

This isn't a conversion problem, per se; it's more of a confusion.

When an HTML file is converted to EPUB and chapter breaks are inserted before <h1> or <h2> tags ([Structure detection] options), at the end of each html "page" in the EPUB I'll see the following code:

Code:

<div class="calibre2" id="calibre_pb_0"></div>

, where "pb_0" increases by two on every subsequent html "page".

This code is not in the original HTML file, the "id" is not referenced anywhere else in the EPUB file (as far as I can tell), and the css for "calibre2" is just "display: block".

Can someone explain what this HTML code is doing, and what—if any—function it has for readability/epub validation/etc. after the converted file has been generated?

03-25-2025, 09:12 AM	#1
ElMiko Evangelist Posts: 474 Karma: 65460 Join Date: Jun 2011 Device: Kindle	Question about HTML-to-EPUB code This isn't a conversion problem, per se; it's more of a confusion. When an HTML file is converted to EPUB and chapter breaks are inserted before <h1> or <h2> tags ([Structure detection] options), at the end of each html "page" in the EPUB I'll see the following code: Code: <div class="calibre2" id="calibre_pb_0"></div> , where "pb_0" increases by two on every subsequent html "page". This code is not in the original HTML file, the "id" is not referenced anywhere else in the EPUB file (as far as I can tell), and the css for "calibre2" is just "display: block". Can someone explain what this HTML code is doing, and what—if any—function it has for readability/epub validation/etc. after the converted file has been generated?