php sun replace tags

Hello friends, could you help me? I have this html code

<div class="media_embed">
    <script height="" width="">
        (function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(d.getElementById(id))return;js=d.createElement(s);js.id=id;js.src='https://embed.playbuzz.com/sdk.js';fjs.parentNode.insertBefore(js,fjs);}(document,'script','playbuzz-sdk'));
    </script>
    <div class="playbuzz" data-id="b" data-show-info="false" height="" width=""></div>
</div>

and I have to change it to be like this:

<figure class="op-interactive">
    <iframe>
        <script height="" width="">
            (function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(d.getElementById(id))return;js=d.createElement(s);js.id=id;js.src='https://embed.playbuzz.com/sdk.js';fjs.parentNode.insertBefore(js,fjs);}(document,'script','playbuzz-sdk'));
        </script>
        <div class="playbuzz" data-id="b" data-show-info="false" height="" width=""></div>
    </iframe>
</figure>

but we are when the div has class media_embed and within div class playbuzz

try it this way:

  $media_embed = $doc->getElementsByTagName('div');
  foreach ($media_embed as $media) {
    $scriptstag = $media->getElementsByTagName('script');
    foreach ($scriptstag as $scripts) {
      $src= $scripts->getAttribute('src');
      $posgif = strpos($src, 'playbuzz');
      if ($posgif === false) {
      } else {
        $tagsscript = $media->childNodes->item(1);
        //print_r($tagsscript);
        $tagdiv = $media->childNodes->item(2);
        //print_r($tagdiv);

          $figureNuevo = $doc->createElement('figure');
          $figureNuevo->setAttribute('class','op-interactive');

          $iframeNuevo = $doc->createElement('iframe');
          $iframeNuevo->setAttribute('class','no-margin');

          $figureNuevo->appendChild($iframeNuevo);

          $iframeNuevo->appendChild($tagdiv);
          //$iframeNuevo->appendChild($tagsscript);

          $scripts->parentNode->replaceChild($figureNuevo, $scripts);
      }
    }                   
   }

Could you help me please? greetings