XML DOM Replace Nodes

The replaceChild() method replaces a specified node.

The nodeValue property replaces text in a text node.

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Replace an Element Node

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

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

Example

xmlDoc=loadXMLDoc("books.xml");

x=xmlDoc.documentElement;

//create a book element, title element and a text nodenewNode=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 nodenewNode.appendChild(newTitle);

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

Example explained:

1. Load "books.xml" into xmlDoc
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

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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

Example

xmlDoc=loadXMLDoc("books.xml");

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

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

Example explained:

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

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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":

Example

xmlDoc=loadXMLDoc("books.xml");

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

x.nodeValue="Easy Italian";

Example explained:

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

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