simplexml_load_file() returns empty object

I have a url to an xml file and when I visit it in my browser it looks good. With the following script however a lot of information seems to be missing:

<?php

    $xml_url = "example.xml";
    $xml = simplexml_load_file($xml_url);
    print_r($xml);

?>

What's going wrong?

EDIT: when I view the xml file in my browser, the data is shown between these: <开发者_如何学C![CDATA[ ]]> Maybe that helps.

---

The print() call does not display all information. Do

echo $xml->asXML();