PHP如何在'描述'中使用img

The Code is like this:

$url = array("http://www.samples.com/rss"
             " ............ "
             " ............ " );

for($j=0;$j<count($url);++$j){
$num = $j + 1;      

 $xmlDoc = new DOMDocument();
 $xmlDoc->load($url[$j]);        

 //get elements from "<channel>"
 $channel=$xmlDoc->getElementsByTagName('channel')->item(0);
 $channel_title = $channel->getElementsByTagName('title')->item(0)->childNodes->item(0)->nodeValue;
 $channel_link = $channel->getElementsByTagName('link')->item(0)->childNodes->item(0)->nodeValue;
 $channel_desc = $channel->getElementsByTagName('description')->item(0)->childNodes->item(0)->nodeValue;


 $x=$xmlDoc->getElementsByTagName('item');

 for ( $i = 0 ; $i < $x->length ; ++$i ){ 

1) for Title $item_title=$x->item($i)->getElementsByTagName('title')->item(0)->childNodes->item(0)->nodeValue;

2) for link $item_link=$x->item($i)->getElementsByTagName('link')->item(0)->childNodes->item(0)->nodeValue;

3) for description $item_desc=$x->item($i)->getElementsByTagName('description')->item(0)->childNodes->item(0)->nodeValue;

    $query[$j]['title'] = $item_title;
    $query[$j]['field'] = "xml";
    $query[$j]['id'] = $item_link;
    $query[$j]['description'] = $item_desc;    
 }  

}

I want to get first img at 3) for descriptoin. Maybe there are many img in desription. But I want first img. How can I pick up img or src?

The description of an RSS document is not specified. In the most cases it will contain an XML fragment (an xml without a root element). It is try and error. Try adding an xml element around and parse the description value as an separate document. This is your best chance.