/***********$file的内容*******/

<books ID="1">
<book ID="01">
<author>Jack1</author>
<title>PHP Hacks</title>
<publisher>O'Reilly</publisher>
</book>
</books>


/****************/
&lt;?php

if (!$dom = domxml_open_file($file)) {
echo "Error while parsing the document\n";
exit;
}

$root = $dom->document_element();
if ($attribute = $root->get_attribute_node('ID')) {
echo 'ID is: ' . $attribute->value() . "\n";
}

?&gt;