(PHP 5 >= 5.1.0)
The SimpleXMLIterator provides recursive iteration over all nodes of a SimpleXMLElement object.
$data
   [, int $options = 0
   [, bool $data_is_url = false
   [, string $ns = ""
   [, bool $is_prefix = false
  ]]]] )$name
   [, string $value
   [, string $namespace
  ]] )$name
   [, string $value
   [, string $namespace
  ]] )$ns = NULL
   [, bool $is_prefix = false
  ]] )$recursive = false
   [, bool $from_root = true
  ]] )