<?php

include 'db/pdo.php';
$IP = $_POST['checkbox'];
if (isset($IP)) {
    foreach ($IP as $row) {
        //$row_IP = $row;
        //$tgl_kembali = date("Y/m/d");
        //echo $tgl_kembali;
        //updateBarangMasuk($row);
        $retur = updateTransaksiRetur($row);
    }
}
if (isset($retur)) {
    header("Location: {$base_url}/retur.php?retur=done");
    //exit();
} else {
    //echo "tidak ada barang dipilih untuk diretur!!!";
    header("Location: {$base_url}/retur.php");
}
<?php

include 'db/pdo.php';
var_dump($_POST);
$no_seri = $_POST['checkbox'];
if (isset($no_seri)) {
    foreach ($no_seri as $row) {
        $nomorseri = $row;
        $tgl_kembali = $_POST['tanggal'];
        //echo $tgl_kembali;
        updateBarangMasuk($row);
        $retur = updateTransaksiRetur($row, $tgl_kembali);
    }
}
if (isset($retur)) {
    header("Location: {$base_url}/retur_maintenance.php?retur=done");
    //exit();
} else {
    //echo "tidak ada barang dipilih untuk diretur!!!";
    header("Location: {$base_url}/retur_maintenance.php");
}