The <defaultSubject> element is used within an attribute enumeration to set the default value for that attribute in cases where no value is specified on the attribute. The default subject must be one of the controlled values within the categories specified for the attribute.



These models represent only the default document types distributed by OASIS. Actual content models will differ with each new document type.
Doctype Content model
subjectScheme ( (data or data-about) (any number) )

Contained by

Doctype Content model
subjectScheme enumerationdef


- map/topicref subjectScheme/defaultSubject


The following example declares that each of the four defined "os" values is valid within the platform attribute; if no value is specified, the default is "linux".

  <subjectdef keys="os">
    <subjectdef keys="linux"/>
    <subjectdef keys="mswin"/>
    <subjectdef keys="zos"/>
    <subjectdef keys="macos"/>
    <attributedef name="platform"/>
    <defaultSubject keyref="linux"/>
    <subjectdef keyref="os"/>


Name Description Data Type Default Value Required?
navtitle Specifies the title of the topic as it will appear in the navigation or tables of contents that are generated from the map. Beginning with DITA 1.2, the preferred way to specify the navigation title in a map is with the navtitle element, available inside the topicmeta element. CDATA #IMPLIED No
href A pointer to the resource represented by the <topicref>. See The href attribute for detailed information on supported values and processing implications. References to DITA content cannot be below the topic level: that is, you cannot reference individual elements inside a topic. References to content other than DITA topics should use the format attribute to identify the kind of resource being referenced. CDATA #IMPLIED No
keys Introduces one or more global identifiers for a resource referenced from a map. See The keys attribute for details on how to use the keys attribute. NMTOKEN #IMPLIED No
processing-role Describes the processing role of the referenced topic. The processing default is "normal". If the value is not specified locally, but is specified on an ancestor, the value will cascade from the closest ancestor.
Normal topic that is a readable part of the information.
The topic is used as a resource for processing purposes, but is not a readable unit of information on its own. This topic should not be included in a rendered table of contents, and the topic should not be rendered on its own.
See Using the -dita-use-conref-target value for more information.
(normal | resource-only | -dita-use-​conref-​target) #IMPLIED No
query This attribute is deprecated. It may be removed in the future. CDATA #IMPLIED No
copy-to Use the copy-to attribute on the <topicref> element to provide a different file name for a particular instance of the topic in the map (for example, to separate out the different versions of the topic, rather than combining them on output). The links and navigation associated with that instance will point to a copy of the topic with the file name you specified.

Use the <linktext> and <shortdesc> in the <topicref>'s <topicmeta> to provide a unique name and short description for the new copy.

type Describes the target of a reference. See The type attribute for detailed information on supported values and processing implications. CDATA #IMPLIED No
scope The scope attribute identifies the closeness of the relationship between the current document and the target resource. See The scope attribute for more information on values. (local | peer | external | -dita-use-​conref-​target) #IMPLIED No
locktitle If locktitle is set to "yes", the <navtitle> element or @navtitle attribute is used if it is present. Otherwise, the navtitle is ignored and the navigation title is retrieved from the referenced file.


The @navtitle attribute is deprecated in favor of the <navtitle> element. When both a <navtitle> element and a navtitle attribute are specified, the <navtitle> element should be used.
The navtitle in the map is used.
The navtitle or title of the topic is used. This is the processing default.
See Using the -dita-use-conref-target value for more information.
(yes | no | -dita-use-​conref-​target) #IMPLIED No
format The format attribute identifies the format of the resource being referenced. See The format attribute for details on supported values. CDATA #IMPLIED No
toc Specifies whether a topic appears in the table of contents (TOC). If the value is not specified locally, but is specified on an ancestor, the value will cascade from the closest ancestor. (yes | no | -dita-use-​conref-​target) #IMPLIED No
univ-atts attribute group (includes select-atts, id-atts, and localization-atts groups) A set of related attributes, described in univ-atts attribute group
global-atts attribute group (xtrf, xtrc) A set of related attributes, described in global-atts attribute group
class, outputclass, keyref Keyref provides a redirectable reference based on a key defined within a map. See The keyref attribute for information on using this attribute. Class and outputclass are described in Other common DITA attributes

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