usemap

operator

Return type: String
 Returns:       Map names.

Syntax
usemap (is | isnt)  (#none | #empty)


Purpose

usemap is an element test, which tests the short reference map associated with the currently opened element (or the element specified by the element-qualifiers) for one of the map names specified in the test.

This test is used to detect the association of usemaps with the elements in the DTD, not in the document instance.

The test succeeds:

  • If the name of the short reference map associated with the element is specified.
  • If the #empty short reference map is associated with the element and #empty is specified.
  • If no short reference map is associated with the element and #none is specified.

Knowing whether or not an element type has an associated usemap declaration is important if the OmniMark program is creating an SGML document from an input SGML document: usemap may affect the way the short reference delimiters are interpreted. When "normalizing" a document, it is usually safest to issue a "<!USEMAP #EMPTY>" declaration at the start of any element with which a usemap declaration (for a map other than #empty) has been associated in the DTD.

The usemap-name is the name of a usemap declaration in the DTD.

Elements which have had short reference maps associated with them by usemap declarations can be identified by the usemap is test. Short reference map names are subject to the NAMELEN and NAMECASE GENERAL declarations in the SGML declaration..

If the element-qualifier specifies an element which does not exist, then the test fails.

The following variations are permitted:

  • The keyword or can be used in place of |.
  • The list of element-names may be enclosed in parentheses to improve readability.

Related Syntax