XML DOM - Properties and Methods
Properties and methods define the programming interface to the
XML DOM.
Examples
The examples below use the XML file
books.xml.
A function, loadXMLDoc(), in an external JavaScript is used to load the XML file.
A function, loadXMLString(), in an external JavaScript is used to load the XML
string.
Load and parse an XML file
Load and parse an XML
string
Programming Interface
The DOM models XML as a set of node objects. The nodes can be accessed with
JavaScript or other programming languages. In this tutorial we use JavaScript.
The programming interface to the DOM is defined by a set standard properties
and methods.
Properties are often referred to as something that is (i.e. nodename
is "book").
Methods are often referred to as something that is done (i.e. delete
"book").
XML DOM Properties
These are some typical DOM properties:
- x.nodeName - the name of x
- x.nodeValue - the value of x
- x.parentNode - the parent node of x
- x.childNodes - the child nodes of x
- x.attributes - the attributes nodes of x
Note: In the list above, x is a node object.
XML DOM Methods
- x.getElementsByTagName(name) - get all elements with a specified
tag name
- x.appendChild(node) - insert a child node to x
- x.removeChild(node) - remove a child node from x
Note: In the list above, x is a node object.
Example
The JavaScript code to get the text from the first <title> element in books.xml:
txt=xmlDoc.getElementsByTagName("title")[0].childNodes[0].nodeValue
After the execution of the statement, txt will hold the value "Everyday
Italian"
Explained:
- xmlDoc - the XML DOM object created by the parser.
- getElementsByTagName("title")[0] - the first <title> element
- childNodes[0] - the first child of the <title> element (the text
node)
- nodeValue - the value of the node (the text itself)
In the example above, getElementsByTagName is a method, while childNodes and
nodeValue are properties.
Parsing an XML File - A Cross browser Example
The following code fragment uses the loadXMLDoc function (described in the
previous chapter) to load books.xml into
the XML parser, and displays data from the first book:
xmlDoc=loadXMLDoc("books.xml");
document.write(xmlDoc.getElementsByTagName("title")
[0].childNodes[0].nodeValue);
document.write("<br />");
document.write(xmlDoc.getElementsByTagName("author")
[0].childNodes[0].nodeValue);
document.write("<br />");
document.write(xmlDoc.getElementsByTagName("year")
[0].childNodes[0].nodeValue);
|
Output:
Everyday Italian
Giada De Laurentiis
2005
|
Try it yourself
In the example above we use childNodes[0] for each text node, even if
there is only one text node for each element. This is because the getElementsByTagName() method always
returns an array.
Parsing an XML String - A Cross browser Example
The following code loads and parses an XML string:
The following code fragment uses the loadXMLString function (described in the
previous chapter) to load books.xml into
the XML parser, and displays data from the first book:
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>";
xmlDoc=loadXMLString(text);
document.write(xmlDoc.getElementsByTagName("title")
[0].childNodes[0].nodeValue);
document.write("<br />");
document.write(xmlDoc.getElementsByTagName("author")
[0].childNodes[0].nodeValue);
document.write("<br />");
document.write(xmlDoc.getElementsByTagName("year")
[0].childNodes[0].nodeValue);
|
Output:
Everyday Italian
Giada De Laurentiis
2005
|
Try it
yourself
| 
HOME
Printer friendly page
