(PHP 5 >= 5.1.2)
SimpleXMLElement::getNamespaces — Returns namespaces used in document
Returns namespaces used in document
If specified, returns all namespaces used in parent and child nodes. Otherwise, returns only namespaces used in root node.
The getNamespaces method returns an array of namespace names with their associated URIs.
Example #1 Get document namespaces in use
<?php
$xml = <<<XML
<?xml version="1.0" standalone="yes"?>
<people xmlns:p="http://example.org/ns" xmlns:t="http://example.org/test">
<p:person id="1">John Doe</p:person>
<p:person id="2">Susie Q. Public</p:person>
</people>
XML;
$sxe = new SimpleXMLElement($xml);
$namespaces = $sxe->getNamespaces(true);
var_dump($namespaces);
?>
上例将输出：
array(1) {
["p"]=>
string(21) "http://example.org/ns"
}