RSS feed没有返回PHP的任何内容？

I am trying to parse this feed with PHP. This is the structure of feed:

<item>
  <title> ... TITLE ... </title>
  <link>  ... LINK .... </link>
  <comments> .. COMMENTS .. </comments>
  .... More tags here ....
  <description><![CDATA[.. HTML ...]]></description>
</item>

This is my PHP code:

$rss  = new DOMDocument();
$rss->loadHTML($feed_url); 
foreach ($rss->getElementsByTagName('item') as $node) {
  $description = $node->getElementsByTagName('description')->item(0)->nodeValue;
  echo $description;
}

but it echoes nothing. I have tried using cURL but even then I can't echo the description tag.

What do I need to change in this code for it to work? Please let me know If I need to post the code of alternate cURL method.

loadHTML is used to load html content, to read rss use below solution

Method 1

$feed_url = 'http://thechive.com/feed/';
$rss  = new DOMDocument();
$rss->load($feed_url);
foreach ($rss->getElementsByTagName('item') as $node) {
    $description = $node->getElementsByTagName('description')->item(0)->nodeValue;
    echo $description;
}

Method 2

$feed_url = 'http://thechive.com/feed/';
$content = file_get_contents($feed_url);
$x = new SimpleXmlElement($content);

foreach($x->channel->item as $entry) {
    echo $entry->description;
}

Hope it will help you...