Define XML and explain the structure of XML.

Define XML and explain the structure of XML.

Define XML and explain the structure of XML.

XML stands for extensible markup language. XML was developed around 1996 and is a subset of SGML. It's documents conform to SGML. XML was made less complicated than SGML to enable its use on the web. XML uses the ISO 10646 (Unicode) standard for encoding characters.

XML Structure

This page provides a description of XML structure including the document parts, the prologue, and provides a simple XML example document.

Document Parts

Prolog

Document Element (root element)

The Prologue : The prologue, equivalent to the header in HTML, may include the following:

An XML declaration (optional) such as: <?xml version="1.0"?>

A DTD or reference to one (optional). An example reference to an external DTD file:

<!DOCTYPE LANGLIST SYSTEM "langlist.dtd">

Processing instructions - An example processing instruction that causes style to be determined by a style sheet:

<?xml-stylesheet type="text/css" href="xmlstyle.css"?>