NOTATION, SHORTREF, and USEMAP Keywords
The keywords in this section are not as commonly used and are not as well documented. None of these keywords are used in the HTML 4.0 DTD. These keywords are not well documented and you should look for other sources if you want detailed information.
The NOTATION declaration creates a parameter that the system will recognize as a content notation. By itself it does nothing more than that and is may be used with other keywords such as ATTLIST or ENTITY. If used as in the example below, the NOTATION may be referenced when specifying the ATTLIST for an element (See the ATTLIST section). The NOTATION syntax is:
<!NOTATION Name SYSTEM Location>
The Loaction is a universal resource indicator (URI) for a file name which may specify a local path or a complete path over the internet such as: "http://ctdp.tripod.com/independent/publishing/guide/file.xml".
The keyword SYSTEM in the example below associates a set of instructions or program name with the notation (pl).
<!NOTATION pl SYSTEM "/usr/bin/perl" >
It is used to set up an association between markup and short strings.
It is used to activate SHORTREFS. This keyword is not commonly used in SGML.