Introduction
Information types and topics
Topics are the building blocks of modular documents, and organising topics by semantic information types is one of the architectural features of DITA.
DITA map files
Syntax and mark-up
Language and punctuation
Graphics and figures
Cross-referencing
Cross-references are a means of binding individual topics into a coherent and navigable document.
Content re-use
Metadata, conditional processing, and indexing
- Conditional processing concepts
  When DITA content is processed to a reading format, rules to exclude or highlight some of the content can be defined in a ditaval file. This conditional processing requires metadata attributes to be set on DITA elements that may possibly be excluded or highlighted.
- Condition (or select) attributes
  The audience, platform, product, otherprops and rev attributes can be applied to most DITA elements. They are used for conditional processing, and are known as the condition (or select) attributes.
- Filtering and flagging
  Content marked with metadata attributes can be conditionally processed so that the content is filtered (excluded) or flagged (highlighted) in the published output.
- Other metadata
  In addition to the select attributes, DITA content includes many forms of metadata. These metadata elements and attributes are used to manage and organise topics, ditamaps and publications.
  - Managing metadata elements and attributes
    The use of metadata elements and attributes may be best managed by a Content Management System.
  - Critical dates
    Metadata relating to important dates in the life cycle of the document are stored in a created and revised elements in the topic prolog or ditamap topicmeta elements.
  - Author, publisher and publication metadata
    Metadata relating to author, publisher and other publication details for a publication or a topic are stored in author, publisher, copyright, and prodinfo elements in the ditamap topicmeta section or the topic prolog section.
  - The outputclass attribute
    When you need an element to appear differently in the output from other elements with the same semantics, you can provide a value in the element's outputclass attribute.
  - The status attribute
    The position of a topic or content element in the development life cycle is recorded in the status attribute.
  - The importance attribute
    The relative importance or priority of a content element is recorded in the importance attribute. Elements with a higher priority may be highlighted in the output.
  - The source element
    When a topic is based on information from another resource, details of that related resource can be stored in the source metadata element in the topic prolog section.
- Indexing
  DITA incorporates powerful features for indexing, including multi-level indexing, and see and see-also redirection. Index entries can be applied in the ditamap, in the topic prolog, and inline within the topic content.
The DITA documentation process
DITA authoring concepts
Moving from style-based authoring to a structured authoring methodology such as DITA requires a radically different approach to writing.

The outputclass attribute

When you need an element to appear differently in the output from other elements with the same semantics, you can provide a value in the element's outputclass attribute.

Most block and phrase elements in DITA have an outputclass attribute. This attribute is used to provide output styling information, when necessary.

When published to an HTML-based output format, the value in the outputclass attribute of an element will be passed through to the CSS class attribute in the HTML code.

You should avoid using the outputclass attribute, as it is not a semantic marker. The presentation of the output should be determined by the publishing tool automatically converting semantic mark-up to formatting rules.