PHP's SimpleXML doesn't save edited data

[sabre1041]

I'm trying to edit some xml data. After this I want to save the data to file. The problem is that the edited data isn't saved by simplexml but the node has changed.\[code\]$spieler = $xml->xpath("/planer/spieltag[@datum='" .$_GET['date']. "']/spielerliste/spieler");for ( $i = 1; $i < 13; $i++ ){ if (!empty($_POST['spieler' .$i ])){ $spieler[$i-1] = $_POST['spieler' .$i]; }}var_dump($spieler);$xml->asXML("data.xml");\[/code\]var_dump() shows the new data, but asXML() doesn't.