Returns the last child node.
var objXMLDOMNode = oXMLDOMNode.lastChild;
The following script example creates a new IXMLDOMNode (element) object, and then inserts it before the last child of the top-level node.
var xmlDoc = new ActiveXObject("Msxml2.DOMDocument.5.0");
var root;
var newNode;
var currNode;
xmlDoc.async = false;
xmlDoc.load("books.xml");
if (xmlDoc.parseError.errorCode <> 0) {
   var myErr = xmlDoc.parseError;
   alert("You have error " + myErr.reason);
} else {
   var root = xmlDoc.documentElement;
   alert(root.xml);
   var newNode = xmlDoc.createNode(1, "VIDEOS", "");
   currNode = root.insertBefore(newNode, root.lastChild);
   alert(root.xml);
}
Set objXMLDOMNode = oXMLDOMNode.lastChild
The following Microsoft® Visual Basic® example creates a new IXMLDOMNode (element) object, and then inserts it before the last child of the top-level node.
Dim xmlDoc As New Msxml2.DOMDocument50
Dim root As IXMLDOMElement
Dim newNode As IXMLDOMNode
Dim currNode As IXMLDOMNode
xmlDoc.async = False
xmlDoc.Load ("books.xml")
If (xmlDoc.parseError.errorCode <> 0) Then
   Dim myErr
   Set myErr = xmlDoc.parseError
   MsgBox("You have error " & myErr.reason)
Else
   Set root = xmlDoc.documentElement
   MsgBox root.xml
   Set newNode = xmlDoc.createNode(NODE_ELEMENT, "VIDEOS", "")
   Set currNode = root.insertBefore(newNode, root.lastChild)
   MsgBox root.xml
End If
HRESULT get_lastChild(
    IXMLDOMNode **lastChild);
lastChild parameter is Null.The property is read-only. If there are no children, it returns Null.
This value depends on the value of the nodeType property.
| NODE_ATTRIBUTE
 NODE_DOCUMENT NODE_DOCUMENT_FRAGMENT NODE_DOCUMENT_TYPE NODE_ELEMENT NODE_ENTITY NODE_ENTITY_REFERENCE  | 
Returns the last child node. If there are no children, returns Null. | 
| NODE_CDATA_SECTION
 NODE_COMMENT NODE_NOTATION NODE_PROCESSING_INSTRUCTION NODE_TEXT  | 
Returns Null. These node types cannot have children. | 
To view reference information for Visual Basic, C/C++, or Script only, click the Language Filter button 
 in the upper-left corner of the page.
Applies to: IXMLDOMAttribute | IXMLDOMCDATASection | IXMLDOMCharacterData | IXMLDOMComment | DOMDocument | IXMLDOMDocumentFragment | IXMLDOMDocumentType | IXMLDOMElement | IXMLDOMEntity | IXMLDOMEntityReference | IXMLDOMNode | IXMLDOMNotation | IXMLDOMProcessingInstruction | IXMLDOMText