| CDATA sections are used to escape blocks of text containing characters that
would otherwise be regarded as markup. The only delimiter that is
recognized in a CDATA section is the "]]>" string that ends the CDATA
section. CDATA sections cannot be nested. Their primary purpose is for
including material such as XML fragments, without needing to escape all
the delimiters.
The DOMString attribute of the Text node holds
the text that is contained by the CDATA section. Note that this may
contain characters that need to be escaped outside of CDATA sections and
that, depending on the character encoding ("charset") chosen for
serialization, it may be impossible to write out some characters as part
of a CDATA section.
The CDATASection interface inherits from the
CharacterData interface through the Text
interface. Adjacent CDATASection nodes are not merged by use
of the normalize method of the Node interface.
Because no markup is recognized within a CDATASection,
character numeric references cannot be used as an escape mechanism when
serializing. Therefore, action needs to be taken when serializing a
CDATASection with a character encoding where some of the
contained characters cannot be represented. Failure to do so would not
produce well-formed XML.One potential solution in the serialization
process is to end the CDATA section before the character, output the
character using a character reference or entity reference, and open a new
CDATA section for any further characters in the text node. Note, however,
that some code conversion libraries at the time of writing do not return
an error or exception when a character is missing from the encoding,
making the task of ensuring that data is not corrupted on serialization
more difficult.
See also the Document Object Model (DOM) Level 2 Core Specification.
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