如何使用php DOM文件？ [关闭]

Can anyone post a example where you parse a string variable with html in it with this DOM document class?

I need to remove certain tags from this variable..

There are no examples on how to use it on the PHP website

$document = new \DomDocument('1.0', 'UTF-8');
$document->loadHTML($source);

$rootElement = $document->documentElement;

$unwantedTags = $rootElement->getElementsByTagName('a');

foreach($unwantedTags as $tag)
{
  $tag->parentNode->removeChild($tag);
}