PHP get variable from form select on live

Question

i need to get variable from select option in form on live, because it is used in next field in the same form. Any clue how to do it ? I guess it can be done with javascript but i have no idea how to use javascript. Thanks in advance. Here's the code of form :

  echo '  <form action="dodaj_harmonogram.php" method="post">';

echo ' <div class="control-group">
    <label class="control-label">Nazwa harmonogramu:</label>
    <div class="controls">
      <input type="text" name="nazwa_harmonogramu" required />
      <p class="help-block"></p>
    </div>
  </div>';
 echo 'Profil:<br /> 
                            <select name="profil">
                              '; pobierz_profile(); 
                              echo'</select><br>';
 echo 'Playlista:<br /> 
 <select name="playlista" id="lista">
 '; pobierz_playlisty($id_playlisty); 
echo'</select><br>';
$czas_playlisty = zaokraglanieczasu(pobierz_czas_utworow_playlisty($id_playlisty));
$czas_sekundy = ceil($czas_playlisty);
echo ' <div class="control-group">
    <label class="control-label">Odstęp (min):</label>
    <div class="controls">
      <input type="number" min="'.$czas_sekundy.'" name="odstep" required />
      <p class="help-block"></p>
    </div>
  </div>';
echo ' <div class="control-group">
    <label class="control-label">Data od</label>
    <div class="controls">
      <input type="date" name="data_od" required />
      <p class="help-block"></p>
    </div>
  </div>';
echo ' <div class="control-group">
    <label class="control-label">Data do</label>
    <div class="controls">
      <input type="date" name="data_do" required />
      <p class="help-block"></p>
    </div>
  </div>';
echo ' Dni:<br />' ;

?>
<table class="table table-bordered" style="width: 20%;">
<thead><th>Nd</th><th>Pn</th><th>Wt</th><th>Śr</th><th>Cz</th><th>Pt</th><th>Sb</th>
</thead>
<tbody>
<td><input type="checkbox" name="nd" value='1'></td>
<td><input type="checkbox" name="pn" value='1'></td>
<td><input type="checkbox" name="wt" value='1'></td>
<td><input type="checkbox" name="sr" value='1'></td>  
<td><input type="checkbox" name="cz" value='1'></td>  
<td><input type="checkbox" name="pt" value='1'></td>
<td><input type="checkbox" name="sb" value='1'></td> 
</tbody>  
</table>
<br>  
<br>   
Godziny:<br />  
<table class="table table-bordered">
<thead><th>0</th><th>1</th><th>2</th><th>3</th><th>4</th><th>5</th><th>6</th><th>7</th><th>8</th><th>9</th><th>10</th><th>11</th>
<th>12</th><th>13</th><th>14</th><th>15</th><th>16</th><th>17</th><th>18</th><th>19</th><th>20</th><th>21</th><th>22</th><th>23</th>
</thead> 
<tbody>                 
<td><input type="checkbox" name="0" value='1'></td>
<td><input type="checkbox" name="1" value='1'></td>
<td><input type="checkbox" name="2" value='1'></td>
<td><input type="checkbox" name="3" value='1'></td>  
<td><input type="checkbox" name="4" value='1'></td>  
<td><input type="checkbox" name="5" value='1'></td>  
<td><input type="checkbox" name="6" value='1'></td> 
<td><input type="checkbox" name="7" value='1'></td>
<td><input type="checkbox" name="8" value='1'></td>
<td><input type="checkbox" name="9" value='1'></td>  
<td><input type="checkbox" name="10" value='1'></td>  
<td><input type="checkbox" name="11" value='1'></td>
<td><input type="checkbox" name="12" value='1'></td> 
<td><input type="checkbox" name="13" value='1'></td> 
<td><input type="checkbox" name="14" value='1'></td>
<td><input type="checkbox" name="15" value='1'></td>
<td><input type="checkbox" name="16" value='1'></td> 
<td><input type="checkbox" name="17" value='1'></td>  
<td><input type="checkbox" name="18" value='1'></td>  
<td><input type="checkbox" name="19" value='1'></td>  
<td><input type="checkbox" name="20" value='1'></td> 
<td><input type="checkbox" name="21" value='1'></td>  
<td><input type="checkbox" name="22" value='1'></td>  
<td><input type="checkbox" name="23" value='1'></td> 
</tbody> 
</table>    
 <br>  
<br>   

    <script>$(function(){
    $( "input[type=checkbox]" ).on( "click", function(){
        if($(this).is(':checked'))
            $(this).parent().css('background-color', 'rgb(36, 255, 0)');
        else
            $(this).parent().css('background-color', 'rgba(202, 202, 202, 0)');
    });
});</script>


   <input type="submit" value="Dodaj "button" class="btn btn-info"></button>
 </form>

Answer 1

Include jQuery

<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>

<script>
// Then use an event handler to check when the select changes 
$('select').on('change', function()
{
  // Show an alert
  alert( "The new value of the select is " + $(this).val() );
  // You should place your logic here to do what you want with that value 
  // E.g. change the page 
  document.location.href = $(this).val();
});
</script>