A DTD is associated with an XML or SGML document by means of a document type declaration (DOCTYPE). The DOCTYPE appears in the syntactic fragment doctypedecl near the start of an XML document. … See more

An example of a very simple external XML DTD to describe the schema of a list of persons might consist of:
Taking this line by line:
1. people_list … See more

An XML DTD can be used to create a denial of service (DoS) attack by defining nested entities that expand exponentially, or by sending the XML parser to an external resource … See more

DTDs describe the structure of a class of documents via element and attribute-list declarations. Element declarations name the allowable set of … See more

The XML DTD syntax is one of several XML schema languages. However, many of the schema languages do not fully replace the XML … See more

Alternatives to DTDs (for specifying schemas) are available:
• XML Schema, also referred to as XML Schema Definition (XSD), has achieved Recommendation … See more

• JATS (Journal Article Tag Suite)
• Semantic Web
• XML Schema (W3C) See more