Content Models and Datatypes

  • Unordered content. Required content without a required order (approximately the SGML "&" connector).

  • Simple datatypes. Dates, integers, prices, etc.

  • Enumerations. Enumerated attribute and element content.

  • Default values. Default attribute and element values.

  • Pattern matching. Attribute and element content validity based on patterns (e.g., regular expressions).

  • Exclusions.

  • Pernicious mixed content. Restrictions on mixed content.

  • Empty mixed content. Mixed content elements that have no required content but may not be completely empty.