Magento2.3 Error – Session Expired When Adding to Cart

The url looks wrong:

http://www.creations-online.co.uk/index.php/creations/ajax/index/add/

Normally the url has this structure:

<protocol>://<baseurl>/<package>/<controller>/<action>/<param1>/<value1>/<param2>/<value2>

But your url has four parts, so either the package's name is creations_ajax or the controller is Ajax/IndexController.php or the action is indexAddAction? Whatever it is, happy fixing.

This is what we do:

When a user clicks 'add to cart' the button is disabled and the box is greyed out. A ' loading.gif ' is displayed onto the page during an Ajax request. When this Ajax request is over the button is re-enabled and the ' loading.gif ' is once again hidden. The cart on the page is then updated and a 'successfully added to cart' message is displayed to the user.

This way the user gets feedback about their actions -- and the consequence of that exact action.

Below is an example of a javascript function that will disable it's own button, display a "loading .gif" for the user, submit the form, and reenable itself once it's execution is complete:

<script type="text/javascript">
    productAddToCartForm.submit = function (button, url) {
                var data = jQuery('#product_addtocart_form').serialize();
                data += '&isAjax=1';

                //this shows a small .gif that tells the user a process is taking place
                jQuery('#ajax_loader').show();

                //this disables the add to cart button
                jQuery('#buttonAddToCart').prop("disabled", true);

                try {
                    jQuery.ajax({
                        url: url,
                        dataType: 'json',
                        type: 'post',
                        data: data,
                        success: function (data) {

                            //this hides the processing .gif
                            jQuery('#ajax_loader').hide();

                            //this removes the 'disable' on the add to cart button
                            jQuery('#buttonAddToCart').prop('disabled', false);
                        }
                    });
                } catch (e) {
                }
                this.form.action = oldUrl;
            }
        }
    }
</script>