HTML - DOM Element isDefaultNamespace() Method

The HTML DOM Element isDefaultNamespace() method is used to check if a specific namespace (a namespace is a set of unique names.) URI is the default namespace for elements within a document or element.

The term URI stands for Uniform Resource Identifier and is a string of characters used to identify resources on the internet or elsewhere.

Syntax

Following is the syntax of the HTML DOM Element isDefaultNamespace() method −

element.isDefaultNamespace(namespaceURI)

Parameters

This function accepts a single parameter as mentioned below −

Method	Description
namespaceURI	It is a string that specifies the namespace URI to check.

Return Value

This method returns true if namespaceURI is the default namespace for an element within a document, otherwise, it returns false.

Example 1: Checking Default Namespace

The following program demonstrates the usage of the HTML DOM Element isDefaultNamespace() method −

<!DOCTYPE html>
<html lang="en">
<head>
<title>HTML DOM Element isDefaultNamespace</title>
</head>
<body>
<h3>HTM DOM Element isDefaultNamespace() method</h3>
<p>Checking default namespace...</p>
<div id="exampleDiv" xmlns="http://www.w3.org/1999/xhtml"></div>
<p id="resultMessage"></p> 
<script>
   const exampleDiv = document.getElementById('exampleDiv');
   const resultMessage = 
   exampleDiv.isDefaultNamespace("http://www.w3.org/1999/xhtml");
   document.getElementById('resultMessage').innerText = 
   "Is this div in the default namespace? " + resultMessage;
</script>
</body>
</html>

The above program displays "true", because the "div" element is in the default namespace.

Example 2: Non-Default Namespace

Here is another example of the HTML DOM Element isDefaultNamespace() method. We use this method to check whether the specific namespace URI is the default namespace for elements within the document −

<!DOCTYPE html>
<html lang="en">
<head>  
<title>HTML DOM isDefaultNamespace</title>
</head>
<body>
<h3>HTML DOM Element isDefaultNamespace method</h3>
<p>Checking default namespace...</p> 
<div id="exampleDiv"xmlns="http://www.example.com/ns"></div>
<p id="resultMessage"></p>    
<script>
   const exampleDiv = 
   document.getElementById('exampleDiv');
   const resultMessage = exampleDiv.isDefaultNamespace(null);  
   document.getElementById('resultMessage').innerText = 
   "Is this div in the default namespace? " + resultMessage;
</script>    
</body>
</html>

The above program displays "false", because the "div" element is not in the default namespace.

Supported Browsers

Method
isDefaultNamespace()	Yes	Yes	Yes	Yes	Yes

html_dom.htm

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