PHP | DOMProcessingInstruction __construct() Function

The DOMProcessingInstruction::__construct() function is an inbuilt function in PHP which is used a new read-only DOMProcessingInstruction object. To create a writable node, use DOMDocument::createProcessingInstruction.
Syntax:

public DOMProcessingInstruction::__construct( string $name, string $value )

Parameters: This function accept two parameters as mentioned above and described below: 

• $name: It specifies the tag name of the processing instruction.
• $value: It specifies the value of the processing instruction.

Below given programs illustrate the DOMProcessingInstruction::__construct() function in PHP:
Program 1: Press Ctrl+U to see the DOM 

php

<?php

// Create a new DOMDocument instance
$dom = new DOMDocument();

// Create a html element
$html = $dom->appendChild(new DOMElement('html'));

// Create a body element
$body = $html->appendChild(new DOMElement('body'));

// Create a new DOMProcessingInstruction node
$pinode = new DOMProcessingInstruction('php',
          'echo "GeeksforGeeks"; ');

// Append the child
$body->appendChild($pinode);

// Render the XML
echo $dom->saveXML();
?>

Output:

Program 2: Press Ctrl+U to see the DOM element. 

php

<?php

// Create a new DOMDocument instance
$dom = new DOMDocument();

// Create a html element
$html = $dom->appendChild(new DOMElement('html'));

// Create a body element
$body = $html->appendChild(new DOMElement('body'));

// Create a new DOMProcessingInstruction node
$pinode = new DOMProcessingInstruction('xml-stylesheet',
       'type="text/xsl" href="base.xsl"');

// Append the child
$body->appendChild($pinode);

// Render the XML
echo $dom->saveXML();
?>

Output:

Reference: https://www.php.net/manual/en/domprocessinginstruction.construct.php