XML Notes

No prebdefined tags, define your own, XML schema or DTD to descrive data

XML used to create XHTML and RSS:

<?xml version="1.0" encoding="ISO-8859-1" ?>

XML declaration defines version and encoding

XML must contain root element (parent of other elements)

Syntax Rules

• closed tags
• case sensitive tags
• elements properly nested
• must have root element
• attributes quoted
• errors stop XML app

XML comment:

<!-- comment -->

CDATA

like comments, everything inside ignored by parser:

<![CDATA[   comment goes here      ]]>

• white spaces are not removed
• attributes have info not part of data
• attributes must be enclosed into qutoes single or double
• meta data should be stored as attributes

Sample Code:

<?xml version = "" encoding = "" ?>
<root element>
    <child>blah</child>
    <elements>blach</elements>
</root element>
<!-- comment -->

Embeded XML (in html):

<xml id="note" src="note.xml"></xml>

XML table:

<table><tr>
    <td>Apples</td>
</tr></table>

XML table with more info:

<h:table>
    <h:name>Tom</h:name>        <!--Prefix tags to avoid element name conflicts-->
    <h:width>80</h:width>
    <h:length>80</h:length>
</h:table>

Namespace of element associates to child elements with same prefix:

xmlns:namespace-prefix = "namespace URL"

• saving xml as unicode to understand foreign chars creates errors in netscape if xml has foreign chars netscape error if encoding is UTF-16

Escape Chars:

&lt;    = <
&gt;    = >
&amp;   = &
&apos;  = '
&quot   = "

XML DTD

Defines structure of XML documet, with list of legal elements alternative to schema

XML STYLE

CSS to style XML:

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

XSL (extensible stylesheet language)

Parse XML via Javascript:

var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");     //create instace of IE parse
var xmlDoc = document.implementation.createDocument("ns", "root", null);    //ns = name space used, root = xml root element
xmlDoc.async="false";   //does not execute until full script is loaded