DTD Attribute Types - NOTATION
The attribute type of NOTATION allows you to use a value that has been declared as a notation in the DTD. A notation is used to specify the format of non-XML data. A common use of notations is to describe MIME types such as image/gif, image/jpeg etc:
Syntax:
To declare a notation:
<!NOTATION name SYSTEM "external_id">
To declare the attribute:
<!ATTLIST element_name
attribute_name NOTATION default_value>
Example:
<!NOTATION GIF SYSTEM "image/gif">
<!NOTATION JPG SYSTEM "image/jpeg">
<!NOTATION PNG SYSTEM "image/png">
<!ATTLIST mountain
photo ENTITY #IMPLIED
photo_type NOTATION (GIF | JPG | PNG) #IMPLIED>
<!ENTITY mt_cook_1 SYSTEM "mt_cook1.jpg">
In the DTD, we have specified that the value of the "photo_type" attribute can be one of the three values supplied. The following XML document would be valid, as it conforms to the above DTD:
<mountains>
<mountain photo="mt_cook_1" photo_type="JPG">
<name>Mount Cook</name>
</mountain>
<mountain>
<name>Cradle Mountain</name>
</mountain>
</mountains>