Zurb Css framework dropdown Issue

Question

I am using Zurb Css framework, As documented on foundation.zurb.com/docs/forms.php I used the same code as provided as below

<label for="customDropdown">Dropdown Label</label>
<select style="display:none;" id="customDropdown">
  <option SELECTED>This is a dropdown</option>
  <option>This is another option</option>
  <option>Look, a third option</option>
</select>
<div class="custom dropdown">
  <a href="#" class="current">This is a dropdown</a>
  <a href="#" class="selector"></a>
  <ul>
    <li>This is a dropdown</li>
    <li>This is another option</li>
    <li>Look, a third option</li>
  </ul>
</div>

But I Cannot see any drop down , The code above is copy pasted from their website.

Thank You.

Answer 1

It was silly mistake I forgot to put class='custom' for the form element.