<table border="1">
    <thead>
        <tr>
            <th>#</th>
            <th>NIS</th>
            <th>Nama Lengkap</th>
            <th>Jenis Kelamin</th>
            <th>Kelas</th>
            <th>Jurusan</th>
        </tr>
    </thead>

    <tbody>
        <?php
            $i = 1;
            while ($siswa = $listSiswa -> fetch_array()) {
        ?>
        <tr>
            <td><?= $i++ ?></td>
            <td><?= $siswa['nis'] ?></td>
            <td><?= $siswa['nama_lengkap'] ?></td>
            <td><?= $siswa['jenis_kelamin'] ?></td>
            <td><?= $siswa['kelas'] ?></td>
            <td><?= $siswa['jurusan'] ?></td>
        </tr>
        <?php } ?>
    </tbody>
</table>