Retrieving an XML document using Ajax

Retrieving an XML document using Ajax
http://www.javascriptkit.com/dhtmltutors/ajaxgetpost3.shtml
When making a server request in Ajax, the data returned can be in either
plain text/html, or an XML document instead. The later is technically
just a text file as well, but with some special instructions, Ajax can
retrieve that well formed XML text file and return it back to you as a
XML object. This enables the XML data to be easily parsed using
standard DOM
methods
.
Here's a simple XML document in RSS format I'll be using for illustration (lets name it "javascriptkit.xml
"):
<?xml version="1.0" encoding="ISO-8859-1"?>

<rss version="0.91">
<channel>
<title>JavaScriptKit.com</title>
<link>http://www.javascriptkit.com</link>
<description>JavaScript tutorials and over 400+ free scripts!</description>
<language>en</language>

<item>
<title>Document Text Resizer</title>
<link>http://www.javascriptkit.com/script/script2/doctextresizer.shtml</link>
<description>This script adds the ability for your users to toggle your
webpage's font size, with persistent cookies then used to remember the
setting</description>
</item>

<item>
<title>JavaScript Reference- Keyboard/ Mouse Buttons Events</title>
<link>http://www.javascriptkit.com/jsref/eventkeyboardmouse.shtml</link>
<description>The latest update to our JS Reference takes a hard look at
keyboard and mouse button events in JavaScript, including the unicode value
of each key.</description>
</item>

<item>
<title>Dynamically loading an external JavaScript or CSS file</title>
<link>http://www.javascriptkit.com/javatutors/loadjavascriptcss.shtml</link>
<description>External JavaScript or CS