DOM - Node Object Method - lookupPrefix

The method lookupPrefix returns the closest prefix defined in the current namespace for the namespace URI. Returns an associated namespace prefix if found or null if none is found.

Syntax

Following is the syntax for the usage of the lookupPrefix method.

nodeObject.lookupPrefix(DOMString namespaceURI)

S.No.	Parameter & Description
1	namespaceURI Based on this parameter prefix is returned. It is of type DOMString.

This method returns the associated namespace prefix or null if none is found.

Example

node_ns.xml contents are as below −

<?xml version = "1.0"?>
<Company>
   <Employee xmlns:e = "http://www.tutorials.com/technical/" category = "technical">
      <e:FirstName>Tanmay</e:FirstName>
      <e:LastName>Patil</e:LastName>
      <e:ContactNo>1234567890</e:ContactNo>
      <e:Email>tanmaypatil@xyz.com</e:Email>
   </Employee>

   <Employee xmlns:n = "http://www.tutorials.com/non-technical/" category="non-technical">
      <n:FirstName>Taniya</n:FirstName>
      <n:LastName>Mishra</n:LastName>
      <n:ContactNo>1234667898</n:ContactNo>
      <n:Email>taniymishra@xyz.com</n:Email>
   </Employee>
</Company>

Following example demonstrates the usage of the lookupPrefix method −

<!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_ns.xml");

         y = xmlDoc.getElementsByTagName("Employee")[0];
         document.write("lookupPrefix is : ")
         document.write(y.lookupPrefix("http://www.tutorials.com/technical/"));
      </script>
   </body>
</html>

Execution

Save this file as nodemethod_lookupprefix.htm on the server path (this file and node_ns.xml should be on the same path in your server). We will get the output as shown below −

lookupPrefix is : e

dom_node_object.htm