<!DOCTYPE html>
<html>
<body>

<?php
$xml=<<<XML
<cars>
   <car name="Volvo">
     <child/>
     <child/>
     <child/>
     <child/>
   </car>
   <car name="BMW">
     <child/>
     <child/>
   </car>
</cars>
XML;

$elem = new SimpleXMLElement($xml);
foreach ($elem as $car)
   {
   printf("%s has %d children.<br>", $car['name'], $car->count());
}
?>

</body>
</html>