echo <script>问题

	case 'add' : //新增     $sku=$_POST['sku_txt'];	 $salesku=$_POST['salesku_txt'];     $fnsku=$_POST['fnsku_txt'];     $diqu=$_POST['diqu_txt'];	 $asin=$_POST['asin'];	 $accout=$_POST['account'];	  $type=$_POST['type'];	 $query = mysql_query("insert into `sku_rule` (`item_code`,`sku`,`asin`,`fnsku`,`delivery_areas`,`account`,`type`)values('$sku','$salesku','$asin','$fnsku','$diqu','$accout','$type')");		if (mysql_affected_rows($conn) != 1){			echo "<script> alert('添加失败!');location.href='sku_comparison.php';</script>";		} else {			echo "<script> alert('添加成功!');location.href='sku_comparison.php';</script>";					}		break;			case 'del' : //删除	$id=$_GET["delivery"];$SQL = "delete from `sku_rule` where id in($id)";		$result = mysql_query($SQL);		if (mysql_affected_rows($conn) != 1){			echo "<script>alert('删除失败!');location.href='sku_comparison.php';</script>";		} else {			echo "<script>alert('删除成功!');location.href='sku_comparison.php';</script>";		}		break;