EpubCCEPUBCheck HTM-051: Microdata without RDFa
Updated:
EPUBCheck HTM-051 is a warning message: “Found Microdata semantic enrichments but no RDFa. EDUPUB recommends using RDFa Lite.” The content uses Microdata but no RDFa, and the EDUPUB profile recommends RDFa Lite. EPUBCheck only reports this when it validates against the EDUPUB profile, set by dc:type metadata or by running it with -profile edupub. It is a warning: the EPUB stays valid.
The official message
Found Microdata semantic enrichments but no RDFa. EDUPUB recommends using RDFa Lite.
- Default severity
- Warning. The EPUB is still valid, but something is likely to cause problems in some reading apps. EPUBCheck exits with 0 unless you pass --failonwarnings.
- EPUBCheck version
- 5.4.0
Typical causes
- An educational book declared as EDUPUB whose semantic markup uses itemscope and itemprop attributes.
- A book validated with -profile edupub by mistake.
How to fix it
- If the book is meant to follow EDUPUB, express the same semantics with RDFa Lite attributes (vocab, typeof, property) instead of, or as well as, Microdata.
- If the book is not an EDUPUB publication, remove the edupub dc:type or run EPUBCheck without -profile edupub.
- Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.
When it's not this
Outside the EDUPUB profile Microdata is allowed in EPUB 3 and this message does not appear.
Terms used here
Other HTM messages
HTM-048SVG Fixed-Layout Documents must have a "viewBox" attribute (on the outermost "svg" element).HTM_054Custom attribute namespace ("…") must not include the string "…" in its domain.HTM-047Viewport metadata "…" has a syntax errorHTM_055The "…" element should not be used (discouraged construct)HTM-046Fixed layout document has no "viewport" meta element.HTM_056Viewport metadata has no "…" dimension (both "width" and "height" properties are required)
Sources
Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.