XML CDATA
All text in an XML document will be parsed by the parser.
Only text within a CDATA section will be ignored by the parser.
PCDATA - Parsed Character Data
XML parsers usually parse all text in an XML document.
When an XML element is parsed, the text between its 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):
The parser breaks it down into sub-elements like this:
<first>Bill</first>
<last>Gates</last>
</name>
Parsed Character Data (PCDATA) is a term used for text data that is parsed by the XML parser.
CDATA - (Unparsed) Character Data
The term CDATA refers to text data that should not be parsed by the XML parser.
Characters such as "<" and "&" are illegal in XML elements.
"<" will cause an error because the parser interprets this character as the beginning of a new element.
"&" will cause an error because the parser interprets this character as the start of a character entity.
Some text, such as JavaScript code, contains a lot of "<" or "&" characters. To avoid errors, the script code can be defined as CDATA.
Everything inside a CDATA section is ignored by the parser.
CDATA section starts with "<![CDATA[and ends with "]]>:
<![CDATA[
function matchwo(a,b)
{
if (a < b && a < 0) then
{
return 1;
}
else
{
return 0;
}
}
]]>
</script>
In the example above, the parser ignores everything in the CDATA section.
Notes about CDATA sections:
A CDATA section cannot contain the string "]]>". Nested CDATA sections are also not allowed.
The "]]>" that marks the end of a CDATA section cannot contain spaces or line breaks.
Other Extensions