Remarks

The ID and IDREF attribute values form a primitive reference mechanism for XML that allow internal linking, for example from a reference in the text to a figure or a table. As another example, when an @id attribute has been used on a <glyph-data> element, that identifier can be referenced by an IDREF-style attribute on a <glyph-ref> element, so that the full glyph data can be pointed to and need not be repeated every time the character is used.

An identifier string is typically 1-32 characters in length and must start with a letter of the alphabet. (It is an XML rule that identifiers may not start with a digit.)

External Identifiers: This attribute holds an internal document identifier that can be used by software to preform a simple link. It should not be confused with elements such as <article-id>, <contrib-id>, and <institution-id> that are used to hold externally defined identifiers such as a DOI (for the article id), an ORCID personal identifier (for the contributor id), or a Ringgold identifier (for an institution id).

Historical Note: This attribute (@id) was significantly remodeled from previous versions of this Tag Set. The current NISO JATS values are backwards compatible with the last NLM version, but not with earlier versions. Specifically, in prior versions the <def-list>, <list>, <list-item>, and <tex-math> elements permitted this attribute to have any value (CDATA), not only valid XML ID values.