Question

OK , here is a html content that i have :

<p> .... </p>
<div id="quick_preview">
<p>the contents </p>
</div>

and what i want is :

<p> .... </p>
<div id="quick_preview">
<description>
  <p>the contents </p>
</description>
</div>

i use this routine to find the div and create description tag, but i don’t know how to insert <description> into div before p:

$dom = new DOMDocument;
$dom->formatOutput = true;
$dom->preserveWhiteSpace = false;
$dom->loadHTML($row['body']);
$divs = $dom->getElementsByTagName('div');
foreach($divs as $div)
{
    if ($div->getAttribute( "id" ) == 'quick_preview') {
        $desc_element = $dom->createElement('description');
    }
}
$dom->saveHTMLFile($html)

Answer 1

This will do what you want:

$dom = new DOMDocument;
$dom->formatOutput = true;
$dom->preserveWhiteSpace = false;
$dom->loadHTML($row['body']);

$xpath = new DOMXPath($dom);

$divs = $xpath->query('//div[@id="quick_preview"]');
foreach ($divs as $div)
{
    $description = $dom->createElement('description');
    while ( $div->hasChildNodes() )
    {
        $description->appendChild($div->firstChild);
    }
    $div->appendChild($description);
}

$dom->saveHTMLFile($html);

You could drop the XPath and use $dom->getElementById('quick_preview') instead.

Note that you can move DOM nodes by simply appending them somewhere else in the document.