All text in an XML document will be parsed by the parser.
But text inside a CDATA section will be ignored by the parser.
PCDATA – Parsed Character Data
XML parsers normally parse all the text in an XML document.
When an XML element is parsed, the text between the XML tags is also parsed:
The parser does this because XML elements can contain other elements, as in this example, where the <name> element contains two other elements (first and last):
and the parser will break it up into sub-elements like this:
Parsed Character Data (PCDATA) is a term used about text data that will be parsed by the XML parser.
CDATA – (Unparsed) Character Data
The term CDATA is used about text data that should not be parsed by the XML parser.
Characters like "<" and "&" are illegal in XML elements.
"<" will generate an error because the parser interprets it as the start of a new element.
"&" will generate an error because the parser interprets it as the start of an character entity.
Everything inside a CDATA section is ignored by the parser.
A CDATA section starts with "<![CDATA[" and ends with "]]>":
if (a < b && a < 0) then
In the example above, everything inside the CDATA section is ignored by the parser.
Notes on CDATA sections:
A CDATA section cannot contain the string "]]>". Nested CDATA sections are not allowed.
The "]]>" that marks the end of the CDATA section cannot contain spaces or line breaks.