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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. |
