Турар Абу

$a = '<span style="font-size:18px"><span style="color:#FF0000">Apollo 11 was the spaceflight that <span style="font-family:courier new,courier,monospace">landed the first humans</span></span><span style="font-family:courier new,courier,monospace">, Americans </span>Neil Armstrong and Buzz Aldrin, on the Moon on July 20, 1969, at 20:18 UTC. Armstrong became the first to step onto the lunar surface 6 hours later on July 21 at 02:56 UTC.</span>';
$dom = new DOMDocument;
$dom->loadHTML($a);
echo '<pre>';

function recurse($a, $i){
	
	var_dump("$i -> " . $a->nodeName );
	if( $a->nodeName != '#text' )
		foreach( $a->childNodes as $t )
			recurse($t, $i+1);
	
}

foreach( $dom->documentElement->childNodes as $i )
	recurse($i, 0);