caontoh validasi form CI

//--filename: views/myform.php
<!DOCTYPE html>
<html>
    <head>
        <meta charset='utf-8'/>
        <title>Simple Validation</title>
    </head>
    <body>
      <?php echo validation_errors(); ?>
      <?php echo form_open('form'); ?>
        <label>tagihan anda<label>
        <input type='text' name='tagihan' id='tagihan' value='<?php echo set_value('tagihan'); ?>'/><br />
        <label>bayar tagihana<label>
        <input type='text' name='bayar' id='bayar' value='<?php echo set_value('bayar'); ?>'/><br />
        <input type='submit' value='submit'/>
      </form>
    </body>
</html>

//--filename: views/formsuccess.php
<html>
<head>
<title>My Form</title>
</head>
<body>
<h3>Your form was successfully submitted!</h3>
<p><?php echo anchor('form', 'Try it again!'); ?></p>
</body>
</html>

//--filename: controller/form.php
<?php
class Form extends CI_Controller {
    function index()
    {
        $this->load->helper(array('form', 'url'));
        $this->load->library('form_validation');
        $this->form_validation->set_rules('bayar', 'Bayar', 'required|less_than['. $this->input->post('tagihan').']');
        if ($this->form_validation->run() == FALSE)
        {
            $this->load->view('myform');
        }
        else
        {
            $this->load->view('formsuccess');
        }
    }
}
?>