The DOMNode::isDefaultNamespace() function is an inbuilt function in PHP which is used to check if the specified namespaceURI is the default namespace or not.
Syntax:
bool DOMNode::isDefaultNamespace( string $namespaceURI )
Parameters: This function accepts a single parameter $namespaceURI which holds the namespace URI.
Return Value: This function return TRUE if namespaceURI is the default namespace, FALSE otherwise.
Below examples illustrate the DOMNode::isDefaultNamespace() function in PHP:
Example 1:
<?php    // Create a new DOMDocument $dom = new DOMDocument();    // Create a paragraph element with a namespace $p_element = $dom->createElementNS(     'my_namespace', 'p', 'neveropen');    // Append the child to DOMDocument $dom->appendChild($p_element);    // Check if the namespace is default or not if($dom->isDefaultNamespace('my_namespace')) {     echo 'Yes, my_namespace is the default namespace.'; } ?> |
Output:
Yes, my_namespace is the default namespace.
Example 2:
<?php   // Create a new DOMDocument $dom = new DOMDocument();    // Create a paragraph element with a namespace $p_element = $dom->createElementNS(     'my_namespace', 'p', 'neveropen');    // Append the child to DOMDocument $dom->appendChild($p_element);    // Check if the namespace is default or not if(!$dom->isDefaultNamespace('some_other_namespace')) {     echo 'No, some_other_namespace is not'                         . ' default namespace.'; } ?> |
Output:
No, some_other_namespace is not the default namespace.
Reference: https://www.php.net/manual/en/domnode.isdefaultnamespace.php
