How can I remove DOM element tags but leave their contents?

Question

I have PHP code which removes all nodes that have at least one attribute. Here is my code:

    
These          


        

Answer 1

Prior to removing the elements you want to pluck out their child nodes and tack them on behind it.

Example:

$data = <<<DATA
<div>
    <p>These line shall stay</p>
    <p class="myclass">Remove this one</p>
    <p>But keep this</p>
    <div style="color: red">and this</div>
    <div style="color: red">and <p>also</p> this</div>
    <div style="color: red">and this <div style="color: red">too</div></div>
</div>
DATA;

$dom = new DOMDocument();
$dom->loadHTML($data, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
$xpath = new DOMXPath($dom);

foreach ($xpath->query("//*[@*]") as $node) {
    $parent = $node->parentNode;
    while ($node->hasChildNodes()) {
        $parent->insertBefore($node->lastChild, $node->nextSibling);
    }
    $parent->removeChild($node);
}

echo $dom->saveHTML();

Outputs:

<div>
    <p>These line shall stay</p>
    Remove this one
    <p>But keep this</p>
    and this
    and <p>also</p> this
    and this too
</div>

https://3v4l.org/9qHRM

(I added some nested elements to demonstrate the safety of this approach.)

---

Couple of asides:

• You don't need $dom->removeChild($dom->doctype) if you load with the additional LIBXML_HTML_NODEFDTD flag.
• Your xpath expression can be simplified to //*[@*]

Answer 2

You could use replaceChild() with the text content of that node:

foreach ($lines_to_be_removed as $line) {
  $line->parentNode->replaceChild($dom->createTextNode($line->textContent),$line);
}

// <div>
//   <p>These line shall stay</p>
//   Remove this one
//   <p>But keep this</p>
//   and this
// </div>

However, this may prove problematic with your // notation of your xpath selector and recursion.

---

Using a more manual approach to copy the child contents of the target nodes into the parent nodes.

$data = '
<div>
  <div>1A</div>
  <div class="foo">1B
    <div>2C</div>
    <div class="foo">2D</div>
    <div>2E</div>
    <div class="foo">2F
      <div>3G</div>
      <div class="foo">3H</div>
    </div>
  </div>
</div>';

$dom = new DOMDOcument();
$dom->loadHTML($data, LIBXML_HTML_NOIMPLIED);
$dom->removeChild($dom->doctype);

SomeFunctionName( $dom->documentElement );

$html = $dom->saveHTML();

function SomeFunctionName( $parent )
{
  $nodesToDelete = array();
  if( $parent->hasChildNodes() )
  {
    foreach( $parent->childNodes as $node )
    {
      SomeFunctionName( $node );
      if( $node->hasAttributes() and count( $node->attributes ) > 0 )
      {
        foreach( $node->childNodes as $childNode )
        {
          $node->parentNode->insertBefore( clone $childNode, $node );
        }
        $nodesToDelete[] = $node;
      }
    }
  }
  foreach( $nodesToDelete as $delete)
  {
    $delete->parentNode->removeChild( $delete );
  }
}

// <div>
//   <div>1A</div>
//   1B
//     <div>2C</div>
//     2D
//     <div>2E</div>
//     2F
//       <div>3G</div>
//       3H
//       <div>3I</div>
//       3J
// </div>

---

If you want to nest the child elements in a new "div" container swap out this porition of code

    foreach( $parent->childNodes as $node )
    {
      SomeFunctionName( $node );
      if( $node->hasAttributes() and count( $node->attributes ) > 0 )
      {
        $newNode = $node->ownerDocument->createElement('div');
        foreach( $node->childNodes as $childNode )
        {
          $newNode->appendChild( clone $childNode );
        }
        $node->parentNode->insertBefore( $newNode, $node );
        $nodesToDelete[] = $node;
      }
    }

// <div>
//   <div>1A</div>
//   <div>1B
//     <div>2C</div>
//     <div>2D</div>
//     <div>2E</div>
//     <div>2F
//       <div>3G</div>
//       <div>3H</div>
//       <div>3I</div>
//       <div>3J</div>
//     </div>
//   </div>
// </div>

Answer 3

This will remove all tags that have class and style attributes, so it's not a bullet proof:

<?php

$data = <<<DATA
<div>
    <p>These line shall stay</p>
    <p class="myclass">Remove this one</p>
    <p>But keep this</p>
    <div style="color: red">and this</div>
</div>
DATA;

$dom = new DOMDOcument();
$dom->loadHTML($data, LIBXML_HTML_NOIMPLIED);
$dom->removeChild($dom->doctype);

$xpath = new DOMXPath($dom);

$lines_to_be_removed = $xpath->query("//*[count(@class)>0 or count(@style)>0]");

foreach ($lines_to_be_removed as $line) {
    $line->parentNode->removeChild($line);
}

// just to check
echo $dom->saveHTML();
?>

Note this line:

 $lines_to_be_removed = $xpath->query("//*[count(@class)>0] or count(@style)>0]");