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Glossary

What is XHTML in EPUB?

Updated:

EPUB content documents are XHTML: HTML written with XML syntax, so every tag must be closed, attributes quoted and the file well-formed. EPUB 3 uses the XHTML syntax of HTML5; EPUB 2 used XHTML 1.1.

Why it matters when you convert a PDF to EPUB

The text a converter extracts from a PDF must be escaped and nested correctly, or the whole chapter fails to parse; one stray "&" or an unclosed tag is enough. Parsing errors appear in EPUBCheck as RSC-005 (schema errors) or RSC-016 (fatal XML errors).

Related terms

EPUBCheck messages about this

  • RSC-005 Error while parsing file: …
  • RSC-016 Fatal Error while parsing file: …
  • HTM-004 Irregular DOCTYPE: found "…", expected "…".
  • HTM-011 Entity is undeclared.
  • RSC-001 File "…" could not be found.
  • RSC-002 Required META-INF/container.xml resource could not be found.
  • RSC-003 No rootfile tag with media type "application/oebps-package+xml" was found in the container.
  • RSC-004 File "…" is encrypted, its content will not be checked.
  • RSC-006 Remote resource reference is not allowed in this context; resource "…" must be located in the EPUB container.
  • RSC-007 Referenced resource "…" could not be found in the EPUB.

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FAQ

What is XHTML in EPUB?

EPUB content documents are XHTML: HTML written with XML syntax, so every tag must be closed, attributes quoted and the file well-formed. EPUB 3 uses the XHTML syntax of HTML5; EPUB 2 used XHTML 1.1.