title: Make bootstrap-select dropdown required
body: <p>I have dropdown list in my form which used <code>bootstrap-select</code> to show the dropdown. I want to make if user submit the form it will check the dropdown is have value or not. I already added <code>required</code> inside the <code>&lt;select&gt;</code> tag but nothing happen if I leave it empty and press submit button.</p>
  
  <p>This is my code :</p>
  
  <pre><code>&lt;div class="form-group"&gt;
      &lt;label for="location"&gt;Location&lt;/label&gt;
      &lt;select name="location" id="location-form" required&gt;
         &lt;option value=""&gt;Choose Location&lt;/option&gt;
         &lt;?php foreach($location as $row) : ?&gt;
         &lt;option value="&lt;?=$row['location_id']?&gt;"&gt;&lt;?=$row['location_name']?&gt;&lt;/option&gt;
         &lt;?php endforeach; ?&gt;
      &lt;/select&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>How to make my select dropdown required and can validate it must filled in if user press submit button ? Thanks before.</p>