PHP变换国际编码

if(isset($_GET['order_id']) && $_GET['order_id']!==''){					$oid=$_GET['order_id'];					$result=$db->Execute("select `d_no` from `delivery` where `oid`=".$oid);					$delivery_no='';					if($result->RecordCount()>0){						while(!$result->EOF){							$delivery_no=$result->fields['d_no'];							$result->MoveNext();							}						if($delivery_no!==''){											$html=file_get_contents('http://tracking.post.japanpost.jp/service/singleSearch.do?searchKind=S004&locale=ja&reqCodeNo1='.$delivery_no);									if($html){									preg_match_all('/][^>]*>(.*?) <\/table>/si',$html,$tables); 									unset($tables[0]);									function getUTFString($string){										$encoding = mb_detect_encoding($string, array('ASCII','UTF-8','Shift-JIS','GB2312','GBK','BIG5'));										return iconv($encoding,'UTF-8',$string);										//return mb_convert_encoding($string, 'utf-8', $encoding);									}									echo getUTFString($tables[1][4]);									}							}						}					}