$html = "<div><div id="id">test</div></div>";
$dom = new DOMDocument;
@$dom->loadHTML($html);
$divtodel = $dom->getElementById('id');
...
echo $dom->saveHTML();
$html = "<div><div id="id">test</div></div>";
$dom = new DOMDocument;
@$dom->loadHTML($html);
$divtodel = $dom->getElementById('id');
...
echo $dom->saveHTML();