Form validation for field create with jquery

You could try something like this:
(Not tested, probably full of bugs)

PHP Code:

$fields = count($this->input->post());
for ($i=1; $i <= $fields; ++$i) 
{
    if ( ( ! empty($this->input->post('article'.$i)) AND ( ! empty($this->input->post('quantity'.$i)) )
    {
        $this->form_validation->set_rule('article'.$i, 'Article '.$i, 'required');
        $this->form_validation->set_rule('quantity'.$i, 'Quantity '.$i, 'required|integer');
    }
} 


I think that should work. May not be the cleanest or neatest way to achieve this but it is one possible way.

Paul.