Return array of all div class names from html source using php

from a html source, using dom and xpath how would I return an array containing all the div class names? I use the following which returns all the div class names that contain “XX”, but don’t know the query to use for $targets to return all. I know this should be simple but I can’t find one that works.

   $doc = new DOMDocument();
   $doc->loadHTML($data);
   $xpath = new DOMXpath($doc);
   $targets = $xpath->query(".//div[contains(@class, 'XX')]");
   $classNames_array = array();
   foreach ($targets as $target) {
   $classNames_array[] = $target->textContent;
   }
   print_r(array_values($classNames_array));

Thanks.

Answer

The query for all classes of divs would be '//div/@class'. Then you get a DomAttr list which you can iterate and get the value as a public property, e.g.

foreach ($entries as $entry) {
    $classes[] = $entry->value;
}