title: Codeigniter get selected values of form_multiselect
body: <p>i'm working on a codeigniter website and i need to use form_multiselect the select shows fine but when i post it and i try to get the selected value on the controller when i do :</p>
  
  <p><code>$category = $this-&gt;input-&gt;get_post('category');
  var_dump($category);</code></p>
  
  <p>i get string(0) "".</p>
  
  <p>here is my codes :</p>
  
  <p><strong>View</strong> </p>
  
  <pre><code>&lt;?php echo form_multiselect('category[]', $categories); ?&gt;
  </code></pre>
  
  <p><strong>Controller</strong></p>
  
  <pre><code>$data['categories'] = $this-&gt;blog_category_model-&gt;getblogcatDropDown($app_key);
  $category = $this-&gt;input-&gt;get_post('category'); 
  var_dump($category);
  die;
  </code></pre>
  
  <p><strong>Model</strong></p>
  
  <pre><code>public function getblogcatDropDown($app_key)
  {
      $query = $this-&gt;db-&gt;query('SELECT * FROM `webapp_blog_categories` WHERE `app_key`=('.$this-&gt;db-&gt;escape($app_key).') ORDER BY `id` ASC')-&gt;result();
      $return[''] = 'Choose blog category';
      foreach ($query as $row) {
          $return[$row-&gt;id] = $row-&gt;cat_name;
      }
  
      return $return;
  }
  </code></pre>
  
  <p><strong>update</strong></p>
  
  <p>when i use html select on the view :</p>
  
  <pre><code>&lt;select multiple name="tst[]"&gt;
       &lt;option value="" disabled selected&gt;Choose your option&lt;/option&gt;
       &lt;option value="1"&gt;Option 1&lt;/option&gt;
       &lt;option value="2"&gt;Option 2&lt;/option&gt;
       &lt;option value="3"&gt;Option 3&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>it works fine , but the generated form not working</p>
  
  <p>can any one help me ? thanks</p>