Description:
------------
Surely this is not a bug, because is too obvious, Perhaps is a fault of W3C spec.

I have a xml file, and I try to parse to get xmlns's attributes. Simplely:

[test.xml]

<?xml version="1.0" encoding="utf-8" ?>
<root xmlns="http://ns" xmlns:ns2="http://ns2">
    <ns2:child />
</root>

Reproduce code:
---------------
$xml=new DOMDocument();
$xml->load("test.xml");

echo $xml->documentElement->getAttribute("xmlns");



Expected result:
----------------
"http://ns"

Actual result:
--------------
""