Description:
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Hi:
   I am a new gur for PHP program, Recently when I write a program that use php function json_encode() to translate a simpleXML object into json code, I found the attributes of the XML leafage node was lose.
   Wait to solve :).
Thank you.

Reproduce code:
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<?
	$xml_str = "<root><node attr='node attribute'>node value</node></root>";
	$xml_obj = simplexml_load_string($xml_str);
	$json = json_encode($xml_obj);
	echo $json;	// so where is node's attribute
	echo "\n=======================================\n";
	$xml_str = "<root><node attr='node attribute'></node></root>";
	$xml_obj = simplexml_load_string($xml_str);
	$json = json_encode($xml_obj);
	echo $json;	// found it, but why?
?>

Expected result:
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{"node":"node value"}
=======================================
{"node":{"@attributes":{"attr":"node attribute"}}}

Actual result:
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inlude node's value and attributes