XML DOM Node List

Wir erstellen jetzt eine Nodeliste alles <title> Elements in „bookdetails.xml“, indem wir die getElementsByTagName („Titel“) Methode verwenden. Das folgende Bild stellt die zurückgebrachte Nodeliste dar:

Das folgende Codefragment erhalten den Text vom ersten <title> Element:

getElementsByTagName("title")[0].childNodes[0].nodeValue

O/P:

Everyday Italian

Get the Length of a Node List

The node list always keeps itself up-to-date. If an element is added or deleted, in the node list or the XML document, the list is automatically updated.

The node list has a useful propertycalled length. The length property returns the number of node in a node list.

The following code fragment get the number of <title> elements in "bookdetails.xml":

getElementsByTagName('title').length

O/P:

When you know the length of node list, you can easily loop through it and extract the values you want.

The following code fragment loops through all <title> elements and print their values:

//the x variable will hold a NodeList
var x=getElementsByTagName('title'); for (i=0;i<x.length;i++)
{
document.write(x[i].childNodes[0].nodeValue)
document.write("<br />")
}

O/P:

Everyday Italian
Harry Potter
XQuery Kick Start
Learning XML

DOM NamedNodeMap

When using the attribute property on an element, we receive a NamedNodeMap object.

A NamedNodeMap object represent an unordered list of attribute nodes.

The nodes in the NamedNodeMap can be accessed using their name.

Note: In a NamedNodeMap, the nodes are not returned in any order.

Get the Length of a NamedNodeMap

The NamedNodeMap always keeps itself up-to-date. If an element is added or deleted , in the node list or the XML document, the list is automatically updated.

The NamedNodeMap also has length property. The length property returns the number of nodes in list.

Look at the following XML file called bookdetails.xml in XML DOM Nodes page.

The following code fragment get the number of attributes in the first <title> element in "bookdetails.xml":

getElementsByTagName('title')[0].attributes.length

O/P:

Get an Item's Value in a NamedNodeMap

The getNamedItem() method of the NamedNodeMap object can be used to retrieve specified node.

The following code fragment shows how to print the value of the "category" attribute in each <book> element:

Last example will create a rectangle with rounded corner:

xmlDoc=loadXMLDoc("bookdetailss.xml");
var x=xmlDoc.getElementsByTagName("book");
for(i=0;i<x.length;i++)
{
//the attlist variable will hold a NamedNodeMap
var attlist=x.item(i).attributes;
var att=attlist.getNamedItem("category");
document.write(att.value + "<br />")
}

O/P:

COOKING
CHILDREN
WEB
WEB