(PHP 5, PHP 7)
SimpleXMLElement::attributes — Identifies an element's attributes
$ns = NULL
   [, bool $is_prefix = FALSE
  ]] )This function provides the attributes and values defined within an xml tag.
Note: SimpleXML 建起了一个给大多数方法添加迭代属性的规则。不能通过使用 var_dump() 或任何可检查对象的其它东西来查看。
nsAn optional namespace for the retrieved attributes
is_prefix
       Default to FALSE
      
Returns a SimpleXMLElement object that can be iterated over to loop through the attributes on the tag.
   Returns NULL if called on a SimpleXMLElement
   object that already represents an attribute and not a tag.
  
Example #1 Interpret an XML string
<?php
$string = <<<XML
<a>
 <foo name="one" game="lonely">1</foo>
</a>
XML;
$xml = simplexml_load_string($string);
foreach($xml->foo[0]->attributes() as $a => $b) {
    echo $a,'="',$b,"\"\n";
}
?>
以上例程会输出:
name="one" game="lonely"