Parsing the XML DOM
Most browsers have a build-in XML parser to read and manipulate XML.
The parser converts XML into a JavaScript accessible object.
Examples
W3Schools examples are browser and platform independent. These examples work in
all modern browsers.
Load and parse an XML file
Load and parse an XML
string
Parsing XML
All modern browsers have a build-in XML parser that can be used to read and manipulate XML.
The parser reads XML into memory and converts it into an XML DOM object that
can be accesses with JavaScript.
There are some differences between Microsoft's XML parser and the parsers
used in other browsers. The Microsoft parser supports loading of both XML files
and XML strings (text), while other browsers use separate parsers. However, all parsers contain functions to traverse XML trees, access,
insert, and delete nodes.
In this tutorial we will show you how to create scripts that will work in both Internet Explorer and
other browsers.
Loading XML with Microsoft's XML Parser
Microsoft's XML parser is built into Internet
Explorer 5 and higher.
The following JavaScript fragment loads an XML document ("books.xml") into
the parser:
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async="false";
xmlDoc.load("books.xml");
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Code explained:
- The first line creates an empty Microsoft XML
document object.
- 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.
- The third
line tells the parser to load an XML document called "books.xml".
The following JavaScript fragment loads a string called txt into
the parser:
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async="false";
xmlDoc.loadXML(txt);
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Note: The loadXML() method is used for loading strings (text), load() is used for loading
files.
XML Parser in Firefox and Other Browsers
The following JavaScript fragment loads an XML document ("books.xml") into
the parser:
xmlDoc=document.implementation.createDocument("","",null);
xmlDoc.async="false";
xmlDoc.load("books.xml");
|
Code explained:
- The first line creates an empty XML
document object.
- 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.
- The third
line tells the parser to load an XML document called "books.xml".
The following JavaScript fragment loads a string called txt into
the parser:
parser=new DOMParser();
xmlDoc=parser.parseFromString(txt,"text/xml");
|
Code explained:
- The first line creates an empty XML
document object.
- The second
line tells the parser to load a string called txt.
Note: Internet Explorer uses the loadXML() method to parse an XML
string, while other browsers uses the DOMParser object.
Parsing an XML File - A Cross browser Example
The following example loads an XML document ("books.xml") into the XML parser:
<html>
<body>
<script type="text/javascript">
try //Internet Explorer
{
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
}
catch(e)
{
try //Firefox, Mozilla, Opera, etc.
{
xmlDoc=document.implementation.createDocument("","",null);
}
catch(e) {alert(e.message)}
}
try
{
xmlDoc.async=false;
xmlDoc.load("books.xml");
document.write("xmlDoc is loaded, ready for use");
}
catch(e) {alert(e.message)}
</script>
</body>
</html>
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Try it yourself
Error: Access Across Domains
For security reasons, modern browsers does not allow access across domains.
This means, that both the web page and the XML file it tries to load, must be
located on the same server.
The examples on W3Schools all open XML files located on the W3Schools domain.
If you want to use the example above on one of your web pages, the XML files
you load must be located on your own server. Otherwise the xmlDoc.load() method,
will generate the error "Access is denied".
Parsing an XML String - A Cross browser Example
The following code loads and parses an XML string:
<html>
<body>
<script type="text/javascript">
text="<bookstore>"
text=text+"<book>";
text=text+"<title>Everyday Italian</title>";
text=text+"<author>Giada De Laurentiis</author>";
text=text+"<year>2005</year>";
text=text+"</book>";
text=text+"</bookstore>";
try //Internet Explorer
{
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async="false";
xmlDoc.loadXML(text);
}
catch(e)
{
try //Firefox, Mozilla, Opera, etc.
{
parser=new DOMParser();
xmlDoc=parser.parseFromString(text,"text/xml");
}
catch(e) {alert(e.message)}
}
document.write("xmlDoc is loaded, ready for use");
</script>
</body>
</html>
|
Try it
yourself
Note: Internet Explorer uses the loadXML() method to parse an XML
string, while other browsers uses the DOMParser object.
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