Other common DITA attributes

The following attributes are not part of an entity group but are common to many elements.

Name	Description	Data Type	Default Value	Required?
class	Not for use by authors. If an editor displays class attribute values, do not edit them. The class attribute supports specialization. Its predefined values allow DITA tools to work correctly with ranges of related content. In a generalized DITA document the class attribute value in the generalized instance may differ from the default value for the class attribute for the element as given in the DTD or schema.	CDATA	Default value differs for each element	No
outputclass	Names a role that the element is playing. The role must be consistent with the basic semantic and expectations for the element. In particular, the outputclass attribute can be used for styling during output processing; HTML output will typically preserve outputclass for CSS processing.	CDATA	#IMPLIED	No
keyref	The keyref attribute is reserved for future use. The OASIS DITA Technical Committee expects to finish designing this attribute in the next release of the DITA standard.	NMTOKEN	#IMPLIED	No
xml:space	This attribute is provided on <pre>, <lines>, and on elements specialized from them. It ensures that parsers in editors and transforms respect the line-end characters that are part of the data in those elements. It is intended to be part of the default properties of these elements, and not for authors to change or delete.	(preserve)	#FIXED 'preserve'	Yes