Hardened JS for newsletter subscribtion

$(document).ready(function() {

    // $(document).acknowledgeinput({
    //  default_state: 'hidden'
    //});

    var formEl = '#__FORMNAME__';
    var submitEl = formEl + ' .btn-submit';
    var spinnerEl = '<span class="spinner fa fa-circle-o-notch fa-spin"><!-- --></span>';
    var spinnerSelector = formEl + ' .spinner';

    $(submitEl).click(function(e) {
        e.preventDefault();

        // get form data and also include the input that was pressed
        var formData = $(this).closest('form').serializeArray();
        formData.push({ name: this.name, value: this.value });

        // create a uniqe tag id for temporary message
        var ts = Math.round(+new Date());
        var messageTagId = 'contact-form-message' + ts;

        // Disable button, and fade in spinner
        $(submitEl).append(spinnerEl).fadeIn(50);
        $(submitEl).attr('disabled', 'disabled');

        $.ajax({
            //type of receiving data
            type: 'POST',

            //page where ajax is running
            url: $(formEl).attr('action') + '?type=6171240&tx_pxanewslettersubscription_subscription%5Baction%5D=ajax',

            //send_data, data which will be send to php
            data: formData,
            dataType: "JSON",
            // if call is ok
            success: function(response) {
                //ajax sends msg from php, which informs user, what has happens
                $(formEl).after('<div id="' + messageTagId + '" class="alert">' + response.message + '<div>');
                if (response.success) {
                    // display message
                    $('#' + messageTagId).addClass('alert-success');
                    // hide form
                    $(formEl).hide();
                } else {
                    // display message and set message to disapear after 5 sec.
                    $('#' + messageTagId).addClass('alert-danger').delay(5000).fadeOut('slow');
                }
                // Hide spinner and enable inputs again
                $(spinnerSelector).fadeOut(50);
                $(submitEl).removeAttr('disabled');
            },

            error: function(jqXHR, textStatus, errorThrown) {
                // Set message and set it to disapear after 5 sec.
                $(formEl).after('<div id="' + messageTagId + '" class="alert alert-danger">' + jqXHR_error_message + '<div>');
                $('#' + messageTagId).delay(5000).fadeOut('slow');
                // hide spinner and enable inputs again
                $(spinnerSelector).fadeOut(50);
                $(submitEl).removeAttr('disabled');
            }
        }); //end ajax
    }); //end submit

});