The DOMNode::replaceChild() function is an inbuilt function in PHP which is used replace the old child node with the passed new node. Further, if the new node is already a child it will not be added the second time. If the replacement succeeds the old node is returned.
Syntax:
DOMNode DOMNode::replaceChild( DOMNode $newnode, DOMNode $oldnode )
Parameters: This function accept two parameters as mentioned above and described below:
- $newnode: It specifies the new node.
- $oldnode: It specifies the old node.
Return Value: This function returns old node or FALSE if an error occur.
Exceptions: This function throws DOM_NO_MODIFICATION_ALLOWED_ERR, if this node is read-only or if the previous parent of the node being inserted is read-only, DOM_HIERARCHY_REQUEST_ERR, if this node is of a type that does not allow children of the type of the $newnode node, or if the node to put in is one of this node’s ancestors or this node itself, DOM_WRONG_DOCUMENT_ERR, if $newnode was created from a different document than the one that created this node, DOM_NOT_FOUND, if $oldnode is not a child of this node.
Below examples illustrate the DOMNode::replaceChild() function in PHP:
Program 1:
<?php   // Create a new DOMDocument instance $document = new DOMDocument();   // Create a root element $element = $document->appendChild(new DOMElement('root'));   // Create the text Node $text1 = $document->createTextNode('Hello ! '); $text2 = $document->createTextNode('Text to be replaced'); $text3 = $document->createTextNode('replaced');   // Append the nodes $element->appendChild($text1); $element->appendChild($text2);   // Replace the child $element->replaceChild($text3, $text2);   // Render the output echo $document->saveXML(); |
Output:
<?xml version="1.0"?> <root>Hello ! replaced</root>
Example 2:
<?php   // Create a new DOMDocument instance $document = new DOMDocument();   // Create a h1 element $element = $document->appendChild(new DOMElement('h1'));   // Create the text Node $text1 = $document->createTextNode('Geeksfor'); $text2 = $document->createTextNode('Text to be removed'); $text3 = $document->createTextNode('Geeks');   // Append the nodes $element->appendChild($text1); $element->appendChild($text2);   // Replace the child $element->replaceChild($text3, $text2);   // Render the output echo $document->saveXML(); ?> |
Output:
<?xml version="1.0"?> <root>neveropen</root>
Reference: https://www.php.net/manual/en/domnode.replacechild.php
