Tag Archives: validation

Add Pattern Support for HTML5 Input Type Number with jQuery

Ran into an issue earlier today that I could not figure out and ended up asking my second question on StackOverflow in seven years.

I was trying to use <input type="number" pattern="[0-9]{8}"> to enforce 8-digit numbers while allowing leading zeros. This was being done on an optional field (no required attribute) and I could not understand why it was bypassing my pattern on the populated field (eg: value “1234” was accepted, pattern ignored).

Peter B. over at SO (kudos) pointed me to the MDN reference that provided the reason… number input does not support pattern attribute

By design! While their reasoning makes sense from a general perspective, the min/max attribute workaround does not help where leading zeros are acceptable (eg: min="00000001"is the same as min="1" for obvious reasons). Unfortunately I need all 8-digits for my purposes. I also tried using minlength and maxlength attributes as a hail-mary to no avail.

Here is a jQuery shim I wrote for my main script file thereby adding pattern support the <input type="number"> Continue reading

How-To: Reload verification image using Codeigniter 2 CAPTCHA helper

Out of the box, CodeIgniter has a good CAPTCHA helper to use in your web applications. Here is a simple example of how to get a new CAPTCHA image without having to reload the page 😉

Basic Controller

class Welcome extends CI_Controller {

    private $captcha_path = 'assets/img/captcha/';

    public function __construct()

    public function index()
        $captcha = create_captcha(array(
            'word'        => strtoupper(substr(md5(time()), 0, 6)),
            'img_path'    => $this->captcha_path,
            'img_url'    => $this->captcha_path
        $data = array(
            'captcha'        => $captcha
        $this->session->set_userdata('captcha', $captcha['word']);
        $this->load->view('welcome', $data);


The View (jQuery used for UI buttons and altering CAPTCHA image ‘src’ attribute)

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/jquery-ui.min.js"></script>
<link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.18/themes/blitzer/jquery-ui.css">
        text: false,
        icons: {
            primary: 'ui-icon-refresh'
        $(this).prev().attr('src', 'welcome/new_captcha?'+Math.random());
<?php echo $captcha['image']; ?>
<a href="#" id="new_captcha">Reload CAPTCHA</a>

Modified Controller Continue reading

Change CodeIgniter’s Form_validation error delimiters globally!

I have seen this question all over the web and am surprised that nobody has actually offered such a simple solution.

Anyway, here is a quick, simple and painless way to set CodeIgniter’s error delimiters (used by the Form_validation library) one time for your entire application. Create “application/libraries/MY_Form_validation.php” with the following contents… Continue reading

CodeIgniter Form Validation Callback Functions with Multiple Arguments

If you’re reading this you most likely already know that you can only send one argument to callback functions using CodeIgniter’s Form Validation Class. If you are not yet familiar with this feature/limitation, here is an example of how the callback works.

Here is our controller with a normal callback (_foo) and our multiple-argument callback function (_valid_login)… Continue reading

Validate email domain using PHP’s checkdnsrr with CodeIgniter

I recently noticed a bunch of garbage registrations for an existing client’s newsletter function written quite some time ago. After making a copy of the subscribers table and “cleaning” the data (proper-cased names, lowercased emails, etc), I started looking at ways to limit these automated registrations.

The client would not be happy with registration confirmation emails, so I decided to make a callback function for use with CodeIgniter’s Form Validation library. Since it was only needed in one location, this method made more sense to me than extending the main library.

Here is the function…

Continue reading