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To read and update - create and manipulate - an
XML document, you will need an XML parser.
Microsoft's XML Parser
Microsoft's XML parser is a COM component that comes with
Internet Explorer 5 and higher. Once you have installed Internet
Explorer, the parser is available to scripts.
Microsoft's XML parser supports all the necessary functions
to traverse the node tree, access the nodes and their attribute
values, insert and delete nodes, and convert the node tree back
to XML.
The following table lists the most commonly used node types
supported by Microsoft's XML parser:
| Node Type |
Example |
| Processing instruction |
<?xml version="1.0"?> |
| Element |
<drink type="beer">Carlsberg</drink> |
| Attribute |
type="beer" |
| Text |
Carlsberg |
MSXML Parser 2.5 is the XML parser that is shipped with
Windows 2000 and IE 5.5.
MSXML Parser 3.0 is the XML parser that is shipped with IE
6.0 and Windows XP.
The MSXML 3.0 parser features:
- JavaScript, VBScript, Perl, VB, Java, C++, etc. support
- Complete XML support
- Full DOM and Namespace support
- DTD and validation
- Complete XSLT and XPath support
- SAX2 support
- Server-safe HTTP
To create an instance of Microsoft's XML parser with
JavaScript, use the following code:
var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
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To create an instance of Microsoft's XML parser with
VBScript, use the following code:
set xmlDoc=CreateObject("Microsoft.XMLDOM")
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To create an instance of Microsoft's XML parser in an ASP
page (using VBScript), use the following code:
set xmlDoc=Server.CreateObject("Microsoft.XMLDOM")
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The following code loads an existing XML document
("note.xml") into Microsoft's XML parser:
<script type="text/javascript">
var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
xmlDoc.async="false"
xmlDoc.load("note.xml")
...
...
...
</script>
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The first line of the script above creates an instance of the
Microsoft XML parser. The third line tells the parser to load an
XML document called "note.xml". The second line turns off
asynchronized loading, to make sure that the parser will not
continue execution of the script before the document is fully
loaded.
XML Parser in Mozilla Browsers
Plain XML documents are displayed in a tree-like structure in
Mozilla (just like IE).
Mozilla also supports parsing of XML data using JavaScript.
The parsed data can be displayed as HTML.
To create an instance of the XML parser with JavaScript in
Mozilla browsers, use the following code:
var xmlDoc=document.implementation.createDocument("ns","root",null)
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The first parameter, ns, defines the namespace used
for the XML document. The second parameter, root, is the
XML root element in the XML file. The third parameter, null, is
always null because it is not implemented yet.
The following code loads an existing XML document
("note.xml") into Mozillas' XML parser:
<script type="text/javascript">
var xmlDoc=document.implementation.createDocument("","",null);
xmlDoc.load("note.xml");
...
...
...
</script>
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The first line of the script above creates an instance of the
XML parser. The second line tells the parser to load an XML
document called "note.xml".
Loading an XML File - A Cross browser Example
The following example is a cross browser example that loads
an existing XML document ("note.xml") into the XML parser:
<html>
<head>
<script type="text/javascript">
var xmlDoc
function loadXML()
{
//load xml file
// code for IE
if (window.ActiveXObject)
{
xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async=false;
xmlDoc.load("note.xml");
getmessage()
}
// code for Mozilla, etc.
else if (document.implementation &&
document.implementation.createDocument)
{
xmlDoc= document.implementation.createDocument("","",null);
xmlDoc.load("note.xml");
xmlDoc.onload=getmessage
}
else
{
alert('Your browser cannot handle this script');
}
}
function getmessage()
{
document.getElementById("to").innerHTML=
xmlDoc.getElementsByTagName("to")[0].firstChild.nodeValue
document.getElementById("from").innerHTML=
xmlDoc.getElementsByTagName("from")[0].firstChild.nodeValue
document.getElementById("message").innerHTML=
xmlDoc.getElementsByTagName("body")[0].firstChild.nodeValue
}
</script>
</head>
<body onload="loadXML()" bgcolor="yellow">
<h1>codedcode Internal Note</h1>
<p><b>To:</b> <span id="to"></span><br />
<b>From:</b> <span id="from"></span>
<hr />
<b>Message:</b> <span id="message"></span>
</p>
</body>
</html>
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Loading XML Text Into the Parser
Internet Explorer supports two ways of loading XML into a
document object: the load() method and the loadXML() method. The
load() method loads an XML file and the loadXML() method loads a
text string that contains XML code.
The following code loads a text string into Microsoft's XML
parser:
<script type="text/javascript">
var txt="<note>"
txt=txt+"<to>Tove</to><from>Jani</from>"
txt=txt+"<heading>Reminder</heading>"
txt=txt+"<body>Don't forget me this weekend!</body>"
txt=txt+"</note>"
var xmlDoc=new ActiveXObject("Microsoft.XMLDOM")
xmlDoc.async="false"
xmlDoc.loadXML(txt)
...
...
...
</script>
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