XML Grammars

Attribute Types

An attribute value can be defined to be of a certain type.

Attribute value can only contain character data
```
<!ATTLIST element-name attribute-name CDATA>
```
The attribute value can only appear once in the XML Document.
```
<!ATTLIST element-name attribute-name ID>
```
References an attribute with an ID value in an XML Document.
```
<!ATTLIST element-name attribute-name IDREF>
```
References multiple attributes with an ID value in an XML Document.
```
<!ATTLIST element-name attribute-name IDREFS>
```
The attribute value must match the name of an unparsed entity.
```
<!ATTLIST element-name attribute-name ENTITY>
```
The attribute value must match a list of names of unparsed entities (separated by spaces).
```
<!ATTLIST element-name attribute-name ENTITIES>
```

The attribute value must match a name token.

<!ATTLIST element-name attribute-name NMTOKEN>

The attribute value must match a list of name tokens (separated by spaces).
```
<!ATTLIST element-name attribute-name NMTOKENS>
```
Specifies an enumerated value, possible enumerated values are separated by '|'.
```
<!ATTLIST element-name attribute-name (yes | no | maybe)>
```