title: Country dropdown is getting validated. But State and City are not
body: <p>I am trying to validate country, state and city. But Country is getting validated whereas city and state are not. </p>
  
  <p>Tried both Client side and Server side validation. Please someone suggest a solution.</p>
  
  <pre><code>&lt;?php
  $options = array();
  $options[''] = BLANK_SELECT;
  if (count($countries)) {
      foreach ($countries as $val) {
          $options[$val-&gt;id] = $val-&gt;country;
      }
  }
  
  echo form_dropdown('pcountryid', $options, $paddress-&gt;countryid, 'id="pcountryid" class="select2 req col-md-6 form-control" style="width:380px;" required');
  ?&gt;
  
  .......
  
  &lt;?php
  $options = array();
  $options['-1'] = BLANK_SELECT;
  
  if (count($states)) {
      foreach ($states as $val) {
          $options[$val-&gt;id] = $val-&gt;state;
      }
  }
  
  echo form_dropdown('pstateid', $options, $paddress-&gt;stateid, 'id="pstateid" class="select2 req col-md-6 form-control" style="width:380px;" required');
  ?&gt;
  
  ......
  
  &lt;?php
  $options = array();
  $options['-1'] = BLANK_SELECT;
  if (count($cities)) {
      foreach ($cities as $val) {
          $options[$val-&gt;id] = $val-&gt;city;
      }
  }
  echo form_dropdown('pcityid', $options, $paddress-&gt;cityid, 'id="pcityid" class="select2 req col-md-6 form-control" style="width:380px;" required');
  ?&gt;
  </code></pre>
  
  <p>//Server side Validation:
  $this->form_validation->set_rules('pcountryid', 'Country', 'required|is_natural'); //Working Fine for Country.
  $this->form_validation->set_rules('pcityid', 'City', 'required|is_natural');
  $this->form_validation->set_rules('pstateid', 'State', 'required|is_natural');</p>
  
  <p>//Client Side Validation:
  the value "-1" for the 1st option for $options array takes care of validating "required" on Country..</p>