PHP:检查XML节点是否存在属性

<?php
$xml_string = '<root><node attribute="value">Content</node></root>';
$xml = new SimpleXMLElement($xml_string);

$node = $xml->node;

if (isset($node['attribute'])) {
    echo 'Node has attribute "attribute"';
} else {
    echo 'Node does not have attribute "attribute"';
}
?>