XML DOM - Add Node


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In this chapter, we will discuss the nodes to the existing element. It provides a means to −

  • append new child nodes before or after the existing child nodes

  • insert data within the text node

  • add attribute node

Following methods can be used to add/append the nodes to an element in a DOM −

  • appendChild()
  • insertBefore()
  • insertData()

appendChild()

The method appendChild() adds the new child node after the existing child node.

Syntax

Syntax of appendChild() method is as follows −

Node appendChild(Node newChild) throws DOMException

Where,

  • newChild − Is the node to add

  • This method returns the Node added.

Example

The following example (appendchildnode_example.htm) parses an XML document (node.xml) into an XML DOM object and appends new child PhoneNo to the element <FirstName>.

<!DOCTYPE html>
<html>
   <head>
      <script>
         function loadXMLDoc(filename) {
            if (window.XMLHttpRequest) {
               xhttp = new XMLHttpRequest();
            } else // code for IE5 and IE6 {
               xhttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
            xhttp.open("GET",filename,false);
            xhttp.send();
            return xhttp.responseXML;
         }
      </script>
   </head>
   <body>
      <script>
         xmlDoc = loadXMLDoc("/dom/node.xml");

         create_e = xmlDoc.createElement("PhoneNo");

         x = xmlDoc.getElementsByTagName("FirstName")[0];
         x.appendChild(create_e);

         document.write(x.getElementsByTagName("PhoneNo")[0].nodeName);
      </script>
   </body>
</html>

In the above example −

  • using the method createElement(), a new element PhoneNo is created.

  • The new element PhoneNo is added to the element FirstName using the method appendChild().

Execution

Save this file as appendchildnode_example.htm on the server path (this file and node.xml should be on the same path in your server). In the output, we get the attribute value as PhoneNo.

insertBefore()

The method insertBefore(), inserts the new child nodes before the specified child nodes.

Syntax

Syntax of insertBefore() method is as follows −

Node insertBefore(Node newChild, Node refChild) throws DOMException

Where,

  • newChild − Is the node to insert

  • refChild − Is the reference node, i.e., the node before which the new node must be inserted.

  • This method returns the Node being inserted.

Example

The following example (insertnodebefore_example.htm) parses an XML document (node.xml) into an XML DOM object and inserts new child Email before the specified element <Email>.

<!DOCTYPE html>
<html>
   <head>
      <script>
         function loadXMLDoc(filename) {
            if (window.XMLHttpRequest) {
               xhttp = new XMLHttpRequest();
            } else // code for IE5 and IE6 {
               xhttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
            xhttp.open("GET",filename,false);
            xhttp.send();
            return xhttp.responseXML;
         }
      </script>
   </head>
   <body>
      <script>
         xmlDoc = loadXMLDoc("/dom/node.xml");

         create_e = xmlDoc.createElement("Email");

         x = xmlDoc.documentElement;
         y = xmlDoc.getElementsByTagName("Email");

         document.write("No of Email elements before inserting was: " + y.length);
         document.write("<br>");
         x.insertBefore(create_e,y[3]);

         y=xmlDoc.getElementsByTagName("Email");
         document.write("No of Email elements after inserting is: " + y.length);
      </script>
   </body>
</html>

In the above example −

  • using the method createElement(), a new element Email is created.

  • The new element Email is added before the element Email using the method insertBefore().

  • y.length gives the total number of elements added before and after the new element.

Execution

Save this file as insertnodebefore_example.htm on the server path (this file and node.xml should be on the same path in your server). We will receive the following output −

No of Email elements before inserting was: 3
No of Email elements after inserting is: 4 

insertData()

The method insertData(), inserts a string at the specified 16-bit unit offset.

Syntax

The insertData() has the following syntax −

void insertData(int offset, java.lang.String arg) throws DOMException

Where,

  • offset − is the character offset at which to insert.

  • arg − is the key word to insert the data. It encloses the two parameters offset and string within the parenthesis separated by comma.

Example

The following example (addtext_example.htm) parses an XML document ("node.xml") into an XML DOM object and inserts new data MiddleName at the specified position to the element <FirstName>.

<!DOCTYPE html>
<html>
   <head>
      <script>
         function loadXMLDoc(filename) {
            if (window.XMLHttpRequest) {
               xhttp = new XMLHttpRequest();
            } else // code for IE5 and IE6 {
               xhttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
            xhttp.open("GET",filename,false);
            xhttp.send();
            return xhttp.responseXML;
         }
     </script>
  </head>
  <body>
     <script>
        xmlDoc = loadXMLDoc("/dom/node.xml");

        x = xmlDoc.getElementsByTagName("FirstName")[0].childNodes[0];
        document.write(x.nodeValue);
        x.insertData(6,"MiddleName");
        document.write("<br>");
        document.write(x.nodeValue);

     </script>
   </body>
</html>
  • x.insertData(6,"MiddleName"); − Here, x holds the name of the specified child name, i.e, <FirstName>. We then insert to this text node the data "MiddleName" starting from position 6.

Execution

Save this file as addtext_example.htm on the server path (this file and node.xml should be on the same path in your server). We will receive the following in the output −

Tanmay
TanmayMiddleName 


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