The difference between DTD and XSD

dtd= type definition (documnet)

Xsd=xml structure definition (XML Schemas definition)

DTDs are equivalent to "vocabulary" and "syntax" in XML, and different industries can define their own "vocabulary" and "grammar" to help the parser validate the validity of XML documents, and thus facilitate communication between industry and industry.

XSD is the reason for DTD substitution, one is that the future conditions can be expanded, two is richer and more useful than DTDs, three is written in XML, four is support data type, and five is support namespace.

DTD versus xsd:DTDs are written using non-XML syntax .
DTDs are not extensible, namespaces are not supported, and only a very limited number of data types are available.

The difference between DTD and XSD