$SimpleXML->asXML() 的格式输出；

If I have something like (from PHP site examples):

$xmlstr = <<<XML
<?xml version='1.0' standalone='yes'?>
<movies></movies>
XML;

$sxe = new SimpleXMLElement($xmlstr);

$sxe->addAttribute('type', 'documentary');

$movie = $sxe->addChild('movie');
$movie->addChild('title', 'PHP2: More Parser Stories');
$movie->addChild('plot', 'This is all about the people who make it work.');

$characters = $movie->addChild('characters');
$character  = $characters->addChild('character');
$character->addChild('name', 'Mr. Parser');
$character->addChild('actor', 'John Doe');

$rating = $movie->addChild('rating', '5');
$rating->addAttribute('type', 'stars');


echo("<pre>".htmlspecialchars($sxe->asXML())."</pre>");

die();

我最终会像这样输出一个长字符串:

<?xml version="1.0" standalone="yes"?>
<movies type="documentary"><movie><title>PHP2: More Parser Stories</title><plot>This is all about the people who make it work.</plot><characters><character><name>Mr. Parser</name><actor>John Doe</actor></character></characters><rating type="stars">5</rating></movie></movies>

$dom = dom_import_simplexml($simpleXml)->ownerDocument;
$dom->formatOutput = true;
echo $dom->saveXML();