How to remove entire div with preg_replace

Question

Ok, as it is WordPress problem and it sadly goes a little deeper, I need to remove each representation of parent div and its inside:

Answer 1

For the UTF-8 issue, I found a hack at the PHP-manual

So my functions looks as follows:

function rem_fi_cat() {
/* This function removes images from _within_ the article.
 * If these images are enclosed in a "wp-caption" div-tag.
 * If the articles are post formatted as "image".
 * Only on home-page, front-page an in category/archive-pages.
 */
if ( (is_home() || is_front_page() || is_category()) && has_post_format( 'image' ) ) {
    $document = new DOMDocument();
    $content = get_the_content( '', true );
    if( '' != $content ) {
        /* incl. UTF-8 "hack" as described at 
         * http://www.php.net/manual/en/domdocument.loadhtml.php#95251
         */
        $document->loadHTML( '' . $content );
        foreach ($doc->childNodes as $item) {
            if ($item->nodeType == XML_PI_NODE) {
                $doc->removeChild($item); // remove hack
                $doc->encoding = 'UTF-8'; // insert proper
            }
        }
        $xpath = new DOMXPath( $document );
        $pDivs = $xpath->query(".//div[@class='wp-caption']");

        foreach ( $pDivs as $div ) {
            $div->parentNode->removeChild( $div );
        }

        echo preg_replace( "/.*
(.*)<\/div>.*/s", "$1", $document->saveHTML() );

    }
}

}