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EPUBCheck · XHTML content documents

EPUBCheck HTM-011: undeclared named entity

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EPUBCheck HTM-011 is an error message: “Entity is undeclared.” A named entity is used that the document does not declare. XML only knows &, <, >, " and ', so HTML names such as   break the XHTML and the chapter may not open at all.

The official message

Entity is undeclared.

EPUBCheck's suggestion: Define the entity or use the numbered entity instead.

Default severity
Error. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.
EPUBCheck version
5.4.0

Typical causes

  • HTML entities such as  , —, … or © pasted into XHTML.
  • Text exported from a word processor or a web page, where HTML entity names are normal.

How to fix it

  1. Open the file EPUBCheck names (the message gives the path, line and column) in a text or EPUB editor such as Sigil, or unzip the EPUB and open it there.
  2. Replace each named entity with a numeric reference (  for a non-breaking space, — for an em dash, … for an ellipsis) or type the character itself in UTF-8.
  3. Search the whole book for & followed by letters to catch the other occurrences at once.
  4. Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.

When it's not this

If the entity is declared in the DOCTYPE through an external file, the message is HTM-003.

Terms used here

Other HTM messages

  • HTM-010 Namespace "…" is unusual for the prefix "epub".
  • HTM-009 The DOCTYPE provided is obsolete or irregular and can be removed.
  • HTM-007 Empty or whitespace-only value of attribute ssml:ph.
  • HTM-004 Irregular DOCTYPE: found "…", expected "…".
  • HTM-003 External entities are not allowed in EPUB v3 documents. External entity declaration found: ….
  • HTM-001 Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: ….

Sources

Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.

FAQ

What does EPUBCheck HTM-011 mean?

EPUBCheck HTM-011 is an error message: “Entity is undeclared.” A named entity is used that the document does not declare. XML only knows &, <, >, " and ', so HTML names such as   break the XHTML and the chapter may not open at all.

Is HTM-011 an error?

HTM-011 is reported as error by default. The EPUB breaks a rule of the specification and is invalid. Stores and Send to Kindle may reject it, and EPUBCheck exits with status 1.