How can I get the current value of "form-control"?

Question

PHP

There are two comboboxes, the data for which are taken from the database, how can I make the second combobox, in the SQL query, substitute the value selected in the first combobox.

'SELECT name FROM equip_cost where type = 'СЮДА ЗНАЧЕНИЕ!''

comboboxes here

<div class = "col-sm-2">
  <select class="form-control" id="combo_type" name="soft_type">
                <?php
    $result_types = DB::select('SELECT type FROM equip_cost GROUP BY type');
    foreach ($result_types as $rtype) {
      echo '<option>';echo $rtype->type;echo ' </option>';
    }
    ?>
  </select>
</div>

<div class="col-sm-3">
  <select class="form-control" id="combo_name" name="soft_name">
    <?php
    $result_names = DB::select('SELECT * FROM equip_cost where type = "'???" ');
    foreach ($result_names as $rname) {
      echo '<option>';echo $rname->name;echo ' </option>';
    }											
    ?> 
  </select>
</div>

Answer 1

you need to use JavaScript, which, when choosing a value in the first combobox, will substitute it in the second and update it