Zend_Dom_Query how to get html code of current node
===

I have nodes, and iterate them in loop.

    $html = <<<HTML
        <div id="test">
        <span>1</span>
        <span>2</span>
        </div>
    HTML;
    $dom= new Zend_Dom_Query($html);
    $results = $dom->query('span');
    foreach($results as $node){
    ...
    }

How get html code of node? (not innerHTML, full HTML code `<span>1</span>`)