XML DOM Advanced

XML DOM Advanced XML DOM-Advanced

In earlier chapters of this tutorial, we introduced the XML DOM and used the getElementsByTagName () method of the XML DOM to retrieve the data from the XML document.

In this chapter we will combine some of the other important XML DOM methods.

You can learn more about the XML DOM in our XML DOM tutorials. get the value of an element

The XML file that is used in the following instance: Books.xml.

The following instance retrieves the text value of the first <title> element: instance txt=xmldoc.getelementsbytagname ("title") [0].childnodes[0].nodevalue;
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gets the value of the property

The following instance retrieves the text value of the "lang" attribute of the first <title> element: instance txt=xmldoc.getelementsbytagname ("title") [0].getattribute (" Lang ");
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change the value of an element

The following example changes the text value of the first <title> element: instance x=xmldoc.getelementsbytagname ("title") [0].childnodes[0];
X.nodevalue= "Easy Cooking";
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Create a new property

The SetAttribute () method of the XML DOM can be used to alter an existing property value, or to create a new property.

The following example creates a new property (edition= "first") and adds it to each <book> element: instance x=xmldoc.getelementsbytagname ("book");

for (i=0;i<x.length;i++)
{
X[i].setattribute ("edition", "First");
}
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Creating Elements

The createelement () method of the XML DOM creates a new element node.

The createTextNode () method of the XML DOM creates a new text node.

The AppendChild () method of the XML DOM adds a child node (after the last child node) to the node.

To create a new element with textual content, you need to create a new element node and a new text node at the same time, and then append it to the existing node.

The following example creates a new element (<edition>) with the following text: First, and then adds it to the initial <book> element: instance newel=xmldoc.createelement (" Edition ");
Newtext=xmldoc.createtextnode ("first");
Newel.appendchild (NewText);

X=xmldoc.getelementsbytagname ("book");
X[0].appendchild (NEWEL);
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Instance explanation Create a <edition> element create a text node with a value of "first" append this text node to the new <edition> element append <edition> element to the one <book> element Delete Element

The following instance deletes the first node of the first <book> element: instance x=xmldoc.getelementsbytagname ("book") [0];
X.removechild (X.childnodes[0]);
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Note: The result of the above instance may vary depending on the browser you are using. Firefox treats new line characters as empty text nodes, which is not the case with Internet Explorer. You can read more about this problem and how to avoid it in our XML DOM tutorials.