i got a url like this one http://somedomain.com/frieventexport.php and the content of this url is a plain XML structure if I check out the source-code of the site:<
One of the best options in my opinion is to use CURL to get the raw XML data from the url:
$curl = curl_init();
curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt( $curl, CURLOPT_URL, "http://somedomain.com/frieventexport.php" );
$xml = curl_exec( $curl );
curl_close( $curl );
You can then use DOMDocument to parse the xml:
$document = new DOMDocument;
$document->loadXML( $xml );
I would also recommend using tags in your XML. Please read the following:
More information about DOMDocument and usage