XMLGuide


XML - Extensible Markup Language

XML is a cross-platform tool for transmitting information and is independent of software and hardware.

XML Document Example

<?xml version="1.0"?>
<note>
    <to>Tove</to>
    <from>Jani</from>
    <heading>Reminder</heading>
    <body>Don't forget me this weekend!</body>
</note>



What is XML?

  • XML stands forExtensible Markup Language(EXtensible Markup Language)
  • XML is amarkup language, very similar to HTML
  • XML is designed todescribe data
  • XML tags are not predefined. You need todefine your own tags。
  • XML usesDocument Type Declaration(DTD) orXML Schemato describe data.
  • XML with a DTD or XML Schema is designed to beself-descriptive。
  • XML is a W3C Standard

XML Does Not Do Anything

XML does not do anything. XML creates structure, stores and carries information.

The XML document example above is a note written in XML from Jani to Tove. Note the title and the email body. It also has information about where it comes from. However, this XML document does not do anything. It is just pure information wrapped in XML markup. Someone must write software to send, receive, or display it:

MESSAGE

To: Tove
From: Jani

Don't forget me this weekend!



XML Tags Are Not Predefined

XML tags are not predefined. You must "invent" your own tags.

The tags used to mark up HTML documents are predefined. HTML file authors can only use tags defined in the HTML standard (such as <P>, <H1>, etc.).

XML allows authors to define their own tags and their own document structure.

In the above example (like <to> and <from>), the tags are not defined in any XML standard. These tags are "invented" by the author of the XML document.

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How to Learn XML?

Study our complete XML tutorial

Other Extensions