XML Tutorials - Herong's Tutorial Examples - Version 5.04, by Dr. Herong Yang
Types of Information in XML Files
This section describes 6 types of information in an XML file: Processing Instruction, Comment, XML Element, Mixed Text, XML Entity, and CDATA Section.
There are 6 types of information in an XML file:
1. Processing Instruction: Used to pass an instruction to applications that processing this file. Processing instructions are written in the following syntax:
where "target" is the name of a target group of applications expected to use this instruction, and "instruction" is the actual instruction to be passed to those applications.
2. Comments: Used only to comment the XML file. Comments will be ignored by application that processing this file. Comments are written in the following syntax:
where "comment" is the text of comment.
3. XML Elements: Used to present a unit of information, with a name, an optional body, and optional attributes. Elements are written in the following syntaxes:
<tag/> <tag attributes/> <tag>content</tag> <tag attributes>content</tag>
where "tag" is the name of the element, "content" is a string of text, or text mixed with XML elements, and "attributes" is one pair of name and value or a list of multiple pairs of name and value written in the following syntax:
name="value" name_1="value 1" name_2="value 2" ... name_n="value n"
4. Mixed Text: A string of text, or text mixed with XML elements, used as contents of elements. Examples of mixed text:
This mixed text only contains characters. This mixed text <br/>contains characters and <b s="1">elements</b>. This mixed text contains entities, &, <</b>.
5. XML Entities: Special escape sequences to represent XML reserved characters. XML entities can be used in element content and attribute values. These are XML pre-defined entities and reserved characters they are representing:
Entity Character & & ' ' > > < < "e; "
5. CDATA Section: A section of text in which any XML reserved characters should be treated as normal characters. CDATA sections are written in the following syntax:
<![CDATA[ text line ... ]]>
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