I want to make a string to
utf8 encoded, but I don't know what the original charset it is.
The original charset of string may be
iso-8859-1, or others I don't know.
mb_detect_encoding($content, 'UTF-8', true) and
iconv($original, "UTF-8", $content);
How to get the original encoding ?
I think this is maybe useful http://php.net/manual/en/function.utf8-encode.php