WooCommerce – Trigger Checkout Form Validation

I ran into this a few times, I have yet to find a straight forward method of handling it. But here is what I’ve done in the past.

You can trigger checkout validation easily by forcing a click on the submit button.

    $('#myButton').on('click', function(){
        $('#place_order').click();
    });

However, this isn’t really useful for you because it will just submit the order if there are no errors.

There is also the checkout_error callback, but it only fires if there is a error.

    $(document.body).on('checkout_error', function () {
        // There was a validation error
    });

Here is what we need to do.

• Detect when the submit button is clicked
• Check for errors
• If there are errors let Woo handle them as normal
• If there are No errors, stop the order from completing
• Show your iframe
• … Re-Validate / Re-submit Order

As soon as the submit button is clicked, we can add a hidden field and set the value to 1. We can detect the submit event by using checkout_place_order. This should go in your JS file.

var checkout_form = $('form.woocommerce-checkout');

checkout_form.on('checkout_place_order', function () {
    if ($('#confirm-order-flag').length == 0) {
        checkout_form.append('<input type="hidden" id="confirm-order-flag" name="confirm-order-flag" value="1">');
    }
    return true;
});

Now, add a function to functions.php that will check that hidden input and stop the order if the value == 1. It stops the order by adding an error.

function add_fake_error($posted) {
    if ($_POST['confirm-order-flag'] == "1") {
        wc_add_notice( __( "custom_notice", 'fake_error' ), 'error');
    } 
}

add_action('woocommerce_after_checkout_validation', 'add_fake_error');

Back in our JS file, we can use the checkout_error callback, if it has 1 error we know it was the fake error we created so we can show the iframe. If it has more than 1 error it means there are other real errors on the page.

$(document.body).on('checkout_error', function () {
    var error_count = $('.woocommerce-error li').length;

    if (error_count == 1) { // Validation Passed (Just the Fake Error Exists)
        // Show iFrame
    }else{ // Validation Failed (Real Errors Exists, Remove the Fake One)
        $('.woocommerce-error li').each(function(){
            var error_text = $(this).text();
            if (error_text == 'custom_notice'){
                $(this).css('display', 'none');
            }
        });
    }
});

In the commented out section, // Show iFrame, I would probably open in it in a lightbox. At some point you will need another submit button that triggers the form submit and set the hidden input.

$('#confirm-order-button').click(function () {
    $('#confirm-order-flag').val('');
    $('#place_order').trigger('click');
});