title: Empty input text field in $_POST (Codeigniter)
body: <p>I have this code in my template</p>
  
  <pre><code>          &lt;?php echo form_open('cart/add'); ?&gt;
            &lt;?php echo form_hidden('id', $product['id']); ?&gt;
            &lt;?php echo form_hidden('title', $product['title']); ?&gt;
            &lt;?php echo form_hidden('price', $product['price']); ?&gt;
            &lt;?php echo form_input('quantity'); ?&gt;
            &lt;?php echo form_submit('cart_submit', 'Add to cart'); ?&gt;
  </code></pre>
  
  <p>When I submit this form to controller <code>quantity</code> variable always empty, no matter what I enter in input field. But there is proper value in headers. Other variables also passed with proper value. May be this is some codeigniter specific configuration?</p>