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XML was designed to describe data and to focus on what data is.
HTML was designed to display data and to focus on how data
looks.
What You Should Already Know
Before you continue you should have a basic understanding of the following:
- HTML / XHTML
- JavaScript or VBScript
If you want to study these subjects first, find the tutorials on our
Home page.
What is XML?
- XML stands for EXtensible Markup Language
- XML is a markup language much like HTML
- XML was designed to describe data
- XML tags are not predefined. You must define your own tags
- XML uses a Document Type Definition (DTD) or an XML Schema
to describe the data
- XML with a DTD or XML Schema is designed to be self-descriptive
- XML is a W3C Recommendation
XML is a W3C Recommendation
The Extensible Markup Language (XML) became a W3C Recommendation 10. February
1998.
The Main Difference Between XML and HTML
XML was designed to carry data.
XML is not a replacement for HTML.
XML and HTML were designed with different goals:
XML was designed to describe data and to focus on what data is.
HTML was designed to display data and to focus on how data looks.
HTML is about displaying information, while XML is about describing
information.
XML Does not DO Anything
XML was not designed to DO anything.
Maybe it is a little hard to understand, but XML does not DO anything. XML
was created to structure, store and to send information.
The following example is a note to Tove from Jani, stored as XML:
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
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The note has a header and a message body. It also has sender and receiver
information. But still, this XML document does not DO anything. It is just pure
information wrapped in XML tags. Someone must write a piece of software to send,
receive or display it.
XML is Free and Extensible
XML tags are not predefined. You must "invent" your own tags.
The tags used to mark up HTML documents and the structure of HTML documents
are predefined. The author of HTML documents can only use tags that are defined
in the HTML standard (like <p>, <h1>, etc.).
XML allows the author to define his own tags and his own document structure.
The tags in the example above (like <to> and <from>) are not defined in any
XML standard. These tags are "invented" by the author of the XML document.
XML is a Complement to HTML
XML is not a replacement for HTML.
It is important to understand that XML is not a replacement for HTML. In
future Web development it is most likely that XML will be used to describe the
data, while HTML will be used to format and display the same data.
My best description of XML is this: XML is a cross-platform, software and
hardware independent tool for transmitting information.
XML in Future Web Development
XML is going to be everywhere.
We have been participating in XML development since its creation. It has been
amazing to see how quickly the XML standard has been developed and how quickly a
large number of software vendors have adopted the standard.
We strongly believe that XML will be as important to the future of the Web as
HTML has been to the foundation of the Web and that XML will be the most common
tool for all data manipulation and data transmission.
XML Joke
Question: When should I use XML?
Answer: When you need a buzzword in your resume.
XML Basic
[XML Tutorial] [XML Introduction] [XML How to use] [XML Syntax] [XML Elements] [XML Attributes] [XML Validation] [XML Validator] [XML Browsers] [XML Viewing] [XML CSS] [XML XSL] [XML Data Island] [XML Parser] [XML in Real Life]
XML Advance
[XML Namespaces] [XML CDATA] [XML Encoding] [XML Server] [XML Application] [XML HTTP Request] [XML Save Data] [XML Behaviors] [XML Technologies] [XML Editors] [XML Summary]
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