Adding an Email Address confirmation field in Gravity Forms

I’m a massive fan of Gravity Forms, as it saves me considerable time with creating pretty complex contact forms. Most recently, I needed to create a contact form for a client where visitors are requested to enter their email address, confirm their email address and then enter their name. Once submitting the form, the users details are added to MailChimp using Gravity Form’s MailChimp Add On.

The motivation for adding an email address confirmation field was to help avoid visitors typing in the wrong email address, and therefore ensuring as many people as possible correctly sign up to the newsletter.

Since Gravity Forms does not currently natively support comparing values between fields, I needed to add my own custom hook to compare and validate the email address fields.

The Solution

First I check that I’m validating the correct form, as it’s pretty common for me to have more than one form per website.

Once the form has been validated, I check that the email address fields match (note that I’ve needed to hardcode absolute field names to refer to the two email address fields). The comparison is performed using a case insensitive search, just so that a minor difference in email address due to a capital letter is ignored.

If the fields are found to not match, the form is invalidated, and the 2nd email address field is marked as invalid with an appropriate error message. This approach works perfectly with AJAX-based forms too.

I hope that you find it useful!

/**
 * Custom validation for gravity forms that will validate
 * the 2nd email address field for a form that has an
 * email address field, and a 'confirm your email address'
 * field as the first 2 fields in a form.
 *
 * @author Dan Harrison (http://www.wpdoctors.co.uk)
 */
function custom_validation($validation_result)
{
    // Extract the form from the validation result
    $form = $validation_result["form"];

    // Ensure we only validate the form entitled
    // 'Newsletter Signup' otherwise return the
    // result of the validation that's already been
    // determined (i.e.
    if ($form['title'] != 'Newsletter Signup') {
        return $validation_result;
    }    

    // We want to ensure that the 1st and 2nd fields
    // match, as it's an email confirmation box
    // First field (0 index) is the email address field
    // Second field (1 index) is the field to confirm
    //  the email address

    // Get the values from $_POST to do the
    // comparison (watch the input numbers, as
    // they're not 0-indexed as above).
    // First field = $_POST['input_2']
    // Second field = $_POST['input_3']

    // Email addresses match (case insensitive, but
    //  use strcmp for case-sensitive comparison)
    if (strcasecmp($_POST['input_2'], $_POST['input_3']) == 0)
    {
        // Nothing to do, fields already match
    }

    // Email addresses don't match.
    else
    {
        // We're doing our own validation now, so
        // override the validation for the whole form.
        // Setting the default to false.
        $validation_result["is_valid"] = false;

        // Invalidate the 2nd email address
        $form["fields"][1]["failed_validation"] = true;
        $form["fields"][1]["validation_message"] =
                   "The email addresses do not match. ".
                   "Please check your email address is correct in both boxes.";
    }

    // Update the form in the validation result
    // with the form object we've modified
    $validation_result["form"] = $form;

    // Return the validation result to
    // continue the action.
    return $validation_result;
}
add_filter('gform_validation', 'custom_validation');