XML DOM Replace Nodes

The replaceChild() method replaces a specified node.

The nodeValue property replaces text in a text node.

Examples

The examples below use the XML file books.xml.
A function, loadXMLDoc(), in an external JavaScript is used to load the XML file.

Replace an element node
This example uses replaceChild() to replace the first <book> node.

Replace data in a text node
This example uses the nodeValue property to replace data in a text node.

Replace an Element Node

The replaceChild() method is used to replace a node.

The following code fragment replaces the first <book> element:

xmlDoc=loadXMLDoc("books.xml");

x=xmlDoc.documentElement;

//create a book element, title element and a text node
newNode=xmlDoc.createElement("book");
newTitle=xmlDoc.createElement("title");
newText=xmlDoc.createTextNode("A Notebook");

//add the text node to the title node,
newTitle.appendChild(newText);
//add the title node to the book node
newNode.appendChild(newTitle);

y=xmlDoc.getElementsByTagName("book")[0]
//replace the first book node with the new node
x.replaceChild(newNode,y);

Example explained:

1. Load "books.xml" into xmlDoc using loadXMLDoc()
2. Create a new element node <book>
3. Create a new element node <title>
4. Create a new text node with the text "A Notebook"
5. Append the new text node to the new element node <title>
6. Append the new element node <title> to the new element node <book>
7. Replace the first <book> element node with the new <book> element node

Try it yourself

Replace Data In a Text Node

The replaceData() method is used to replace data in a text node.

The replaceData() method has three parameters:

• offset - Where to begin replacing characters. Offset value starts at zero
• length - How many characters to replace
• string - The string to insert

xmlDoc=loadXMLDoc("books.xml");

x=xmlDoc.getElementsByTagName("title")[0].childNodes[0];

x.replaceData(0,8,"Easy");

Example explained:

1. Load "books.xml" into xmlDoc using loadXMLDoc()
2. Get the text node of the first <title> element node
3. Use the replaceDat method to replace the eight first characters from the text node with "Easy"

Try it yourself

Use the nodeValue Property Instead

It is easier to replace the data in a text node using the nodeValue property.

The following code fragment will replace the text node value in the first <title> element with "Easy Italian":

xmlDoc=loadXMLDoc("books.xml");

x=xmlDoc.getElementsByTagName("title")[0].childNodes[0];

x.nodeValue="Easy Italian";

Example explained:

1. Load "books.xml" into xmlDoc using loadXMLDoc()
2. Get the text node of the first <title> element node
3. Use the nodeValue property to change the text of the text node

Try it yourself

You can read more about changing node values in the Change Node chapter.

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