<?php
	function merge_html($html) {
		$dom = new DOMDocument;
		$dom->loadHTML("<div id=\"tmptmptmp\">" . $html . "</div>", LIBXML_HTML_NOIMPLIED|LIBXML_HTML_NODEFDTD);
		$xp = new DOMXPath($dom);
		$links = $xp->query('//div');
		foreach ($links as $link) {
			$class = $link->getAttribute('class');
			$nested = $xp->query('.//div', $link);
			foreach ($nested as $n) {
				if ($n->getAttribute('class') == $class) {
				   //$html = $doc->getElementsByTagName("html")->item(0);
                   $fragment = $dom->createDocumentFragment();
                   while ($n->childNodes->length > 0) {
                     $fragment->appendChild($n->childNodes->item(0));
                   }
                  $n->parentNode->replaceChild($fragment, $n);
				}
			 }
		}
		return preg_replace('/^\s*<div\s+id="tmptmptmp">\s*|\s*<\/div>\s*$/', '', $dom->saveHTML());
	}
	$html = '
	    <div class="dotted-highlight">
	      Here is a check list to determine whether you want this career or not.
	      <div class="dotted-highlight">
	        Tick all those apply to you. The more boxes you tick, the better suited you are to this career.
	        <ul>
	          <li>
	            You are hyper active and are always on your toes.
	          </li>
	          <li>
	            You are mentally and physically strong enough to withstand rigorous exercise.
	          </li>
	        </ul>
	      </div>
	      <div class="dotted-highlight">
	        You do not mind working in the early morning, late evenings, and on weekends and holidays.
	      </div>
	    </div>
	          <h2>
        What work does it involve?
      </h2><strong>To become a fitness instructor or a personal trainer, your main job is to help people with their exercise routines.</strong>
	';
	$html = merge_html($html);
	var_dump($html);
?>

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