candidate recommendation

In the standards process, a candidate recommendation is a specification that has achieved enough consensus by its working group to be released for public review. See also recommendation, standards body.


A specially formatted text file (usually local) whose information is used to resolve public identifiers into system identifiers. The catalog file format was formally specified by OASIS Technical Resolution 9401:1997. See also formal public identifier, URI.

CDATA (character data)

CDATA is an entity data type consisting of nonparsed characters. Entity references included in this data will not be resolved. A CDATA marked section looks like this:

<![CDATA unparsed content]]>

See also PCDATA.

character encoding

The representation of characters as unique numbers in a character set. See also character set.

character entity

A notation for any character or symbol that uses its character set number or abbreviation. The common syntax for character encoding is an ampersand (&), followed by the name or a #-sign and number, terminated with a semicolon. For example, the copyright symbol © can be output in a document by using either &#169; or &copy;.

character set

A collection of letters, numbers, and symbols representing a language or set of languages, mapped to specified numbers that can be understood by computer programs. See also character encoding.


Specially marked text in the document source that is not interpreted by the parser. XML comments are surrounded by <!-- and --> delimiters. Everything inside a comment is ignored by the parser, including tagged elements. Comments can provide additional information about a document's markup and content and are a useful way to remove content from a document's output without fully deleting it. See also markup.

container element

An element that contains character data or other elements is called a container. It is a root to its own subtree in the document. See also content, content model, element.


Anything in a document that is not markup. Take away the tags, comments, and processing instructions, and what's left is content or character data. Markup allows content to be repurposed many ways. See also container element, content model.

content model

The technical specification of a DTD that describes an element's contents. The content model specifies which kinds of elements and data can occur within an element, how many can occur, and how they are ordered. See also element, content.

CSS (Cascading Style Sheets)

This specification provides a standard way of specifying the presentation of a document by applying formatting rules to elements. Cascading refers to how an element is formatted when several rules overlap, such as a locally applied rule and a global rule. See also presentation, stylesheet.

current node

The node in which an expression is being evaluated. See also current node set, node, XSLT.

current node set

The set of selected nodes that provide the immediate context for an expression. See also current node, node, XSLT.