XML has a simple markup syntax that allows you to store information as a tree of tagged nodes.
Consider the XML document library1.xml, shown in the following example, that describes the contents of a library.
<?xml version="1.0"?>
<!--An example XML document-->
<library>
<book isbn="0-246-13655-3">
<title>Mystery</title>
<author>Peter Straub</author>
</book>
<book isbn="1-876590-17-3">
<title>False Memory</title>
<author>Dean Koontz</author>
</book>
</library>
In this example:
The first line of the file is the XML declaration with version information.
The second line defines a comment node.
The next line contains a <library> tag, which indicates the start of an XML element node named library that ends when a matching </library> tag is found.
The <library> element is the root element of the document and contains two <book> element child nodes, each containing a <title> and an <author> node.
Each <book> element node has an attribute with name isbn and its International Standard Book Number (ISBN) value.
The <title> and <author> elements each contain text data.