SCRIPT INSERT PHP

<?php
include "koneksi.php";
$id_izin= $_POST ['id_izin'];
$nama = $_POST ['nama'];
$kelas= $_POST ['kelas'];
$jurusan= $_POST ['jurusan'];
$ortu = $_POST ['ortu'];
$tgl_izin= $_POST ['tgl_izin'];
$tgl_masuk= $_POST ['tgl_masuk'];
mysqli_query ($koneksi, "insert into izin values ('$id_izin', '$nama', '$kelas','$jurusan','$ortu','$tgl_izin','$tgl_masuk') ");
header ("location:showizin.php");
?>