All of the text, other than markup,contained in an element in XML documents. For an element to contain character data,the element's definition with the DTD must include CDATA in it's content model. All elements do not necessarily have to contain character data.
Characters that appear in a part of an SGML document in which text is not parsed and markup is not recognized. This includes the values of an attribute whose content has been defined in a DTD as being character data, or the contents of a marked CDATA section of a document-one that has been delimited and identified as character data. CDATA is useful when it is desirable to pass data to an application without having to deal with the character set issues that would be introduced by parsing, such as when computer code is included within the text of a document. The XML specification uses the expression "character data" in a more general and slightly different way than SGML when it states that "All text that is not markup constitutes the character data of the document." See also Parsable Character Data (PCDATA).
Information in a document that should not be parsed at all. This allows the use of the markup characters & , and within the text, even though no elements or entities may appear in the section. CDATA declarations may appear in attributes, and CDATA-marked sections may appear in documents.