DTD - attributes
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Document type definitions (DTDs) define legal building blocks for XML documents. It uses a series of legal elements to define the structure of the document.
A DTD can be declared in an XML document as a line or as an external reference.
DTD - attributessyntax
In a DTD, attributes are declared using the ATTLIST declaration.
DTD - attributesexample
<!ATTLIST element-name attribute-name attribute-type attribute-value> DTD 实例: <!ATTLIST payment type CDATA "check"> XML 实例: <payment type="check" />