PHP - Como cargar el id de la base de datos en un modal?

<link rel="stylesheet" href="css/bootstrap.min.css">

        <form   method="POST">

            <h1>FORMACIÓN DEL PERSONAL</h1>

            <div class="contentform">

                <div class="leftcontact">

                    <div class="form-group">

                        <p>Tipo de cargo</p>

                        <select id="cargo" name="cargo" required>

                        </select>

                    </div>

                    <div class="form-group">

                        <p>Capacitacion</p>

                        <select id="capa" name="capa" required>

                        </select>

                    </div>

                </div>

                <div class="rightcontact">

                    <button type="button" id="clic" data-toggle="modal" data-target="#miModal">

                        Agregar personal

                    </button>

                </div>

            </div>

            <button type="submit" class="bottom">Guardar</button>

        </form>

        <script src="js/ajax.js"></script>

        <script src="js/carga.js"></script>

        <script src="js/caps.js"></script>

        <script src="js/bootstrap.min.js"></script>

<?php include "zius.php";?>

$(document).ready(function(){

  $.ajax({

    type: 'POST',

    url: 'fre.php',

  })

  .done(function(listas_ar){

    $('#cargo').html(listas_ar)

  })

  .fail(function(){

    alert('Hubo un error al cargar los cargos')

  })

$('#cargo').on('change', function(){

    var id = $('#cargo').val()

    $.ajax({

      type: 'POST',

      url: 'cap.php',

      data: {'Id_cargo': id}

    })

    .done(function(listas_rep){

      $('#capa').html(listas_rep)

    })

    .fail(function(){

      alert('Hubo un errror al cargar las capacitaciónes')

    })

  })

})

$('#cargo').on('change', function(){

  var id = $('#cargo').val()

  $.ajax({

        url: 'zius.php',

        type: 'POST',

        dataType: '',

        data: {'Id_cargo': id}

      })

      .done(function(response) {

$('#miModal').modal('show');

});

});

$('#clic').click(function(){

    $('#miModal').modal('show');

});

<?php

function aer(){

  include 'conexion/db.php';

  $boo = 'SELECT * FROM cargo

  		  order by Cargo asc';

  $result = $cone->query($boo);

  $listas = '<option value="0">Elige una opción</option>';

  while($row = $result->fetch_array(MYSQLI_ASSOC)){

    $listas .= "<option value='$row[Id_cargo]'>$row[Cargo]</option>";

  }

  return $listas;

}

echo aer();

<?php

function capa(){

  include 'conexion/db.php';

  $id = $_POST['Id_cargo'];

  $boo = "SELECT * FROM capa where Id_cargo = '$id'

          order by Forma asc";

  $result = $cone->query($boo);

  $crash = '<option value="0">Elige una opción</option>';

  while($row = $result->fetch_array(MYSQLI_ASSOC)){

    $crash .= "<option value='$row[Id_capa]'>$row[Forma]</option>";

  }

  return $crash;

}

echo capa();

<?php

  include "conexion/db.php";

  $id= $_POST['Id_cargo'];

  $sql = "SELECT a.Id_foto, a.Nombre_em, b.Id_cargo, b.Cargo

          FROM personal as a 

          INNER JOIN cargo b on b.Id_cargo = a.Id_cargo

          where b.Id_cargo ='$id'";

  $resul = $cone->query($sql);

?>

<div class="modal fade" id="miModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">

    <div class="modal-dialog" role="document">

        <div class="modal-content">

            <div class="modal-header">

                <button type="button" class="close" data-dismiss="modal" aria-label="Close">

                    <span aria-hidden="true">&times;</span><br>

                </button>

                <h4><center>Empleados</center></h4>

                <div><br ><br >

                    <input type="text" id="buscar" class="buscar" style="width: 100%; margin-left: -90% !important;" placeholder="Buscar...">

                </div>

            </div>

            <div class="modal-body">

                <table id="tabla" border="1" class='tabla_datos'>

                    <thead>

                        <tr id="titulo">

                            <th><center>Nº Foto</center></th>

                            <th><center>Nombre</center></th>

                            <th><center>Cargo</center></th>

                            <th>Comando</th>

                        </tr>

                    </thead>

                    <tbody>

                        <?php while ($row = $resul->fetch_assoc())

                        {?>

                            <tr>

                                <td><?php $codigo = $row['Id_foto']; echo $codigo; ?></td>

                                <td><?php $equi = $row['Nombre_em']; echo $equi; ?></td>

                                <td><?php $secc = $row['Cargo']; echo $secc; ?></td>

                                <td><button class="bor" onclick="agregarEquipo('<?php echo $codigo;?>', '<?php echo $equi;?>')" data-dismiss="modal">Agregar</button></td>

                            </tr>

                        <?php }?>

                    </tbody>

                </table>

            </div>

        </div>

    </div>

</div>

<script src="js/buscar.js"></script>