Ajax call not working

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add_action('wp_ajax_dynamic_price', 'get_update_dynamic_price_xyz');
add_action('wp_ajax_nopriv_dynamic_price', 'get_update_dynamic_price_xyz');

function get_update_dynamic_price_xyz()
{
    global $product;

    /**
    * Get the discount details of given product with custom price
    * @param $price float/integer
    * @param $product object (Product object Example: wc_get_product($product_id))
    * @param $quantity int
    * @param $custom_price float/integer (0 for calculate discount from product price)
    * @param $return_details string (Default value 'discounted_price' accepted values="discounted_price",'all')
    * @param $manual_request boolean (Default value false: pass this as true for get discount even if there is no item in cart)
    * @param $is_cart boolean (Default value true)
    * @return array|float|int - is product has no discounts, returns $price;else return array of discount details based on $return_details
    */
    $qty = $_POST['quantity'];
    $price = apply_filters('advanced_woo_discount_rules_get_product_discount_price_from_custom_price', $product->get_price(), $product->get_id(), $qty, 0, 'discounted_price', 'true', 'true');

    if ($price == '')
    {
        $price = $product->get_price();
    }

    echo $price;
}

function action_woocommerce_single_product_summary()
{
    global $product;

    /**
    * Get the discount details of given product with custom price
    * @param $price float/integer
    * @param $product object (Product object Example: wc_get_product($product_id))
    * @param $quantity int
    * @param $custom_price float/integer (0 for calculate discount from product price)
    * @param $return_details string (Default value 'discounted_price' accepted values="discounted_price",'all')
    * @param $manual_request boolean (Default value false: pass this as true for get discount even if there is no item in cart)
    * @param $is_cart boolean (Default value true)
    * @return array|float|int - is product has no discounts, returns $price;else return array of discount details based on $return_details
    */

    $price = apply_filters('advanced_woo_discount_rules_get_product_discount_price_from_custom_price', $product->get_price(), $product->get_id(), 1, 0, 'discounted_price', 'true', 'true');

    if ($price == '')
    {
        $price = $product->get_price();
    }

    $currency_symbol = get_woocommerce_currency_symbol();

    // let's setup our div
    echo sprintf('<div id="product_total_price" style="margin-bottom:20px;">%s %s</div>', __('Product Total:', 'woocommerce'), '<span class="price">' . $currency_symbol . $price . '</span>');
?>
    <script>
        jQuery(function($) {
            // jQuery variables
            var price = <?php echo $price; ?>,
                currency = '<?php echo $currency_symbol; ?>',
                quantity = $('[name=quantity]').val();

            // Code to run when the document is ready
            var product_total = parseFloat(price * quantity);
            $('#product_total_price .price').html(currency + product_total.toFixed(2));

            // On change
            $('[name=quantity]').change(function() {
                var quantity = this.value;

                $.ajax({
                    url: '<?php echo admin_url('admin-ajax.php') ?>',
                    type: 'POST',
                    data: {
                        quantity: quantity,
                        action: 'dynamic_price'
                    },
                    success: function(data) {
                        //var price = data;
                        alert('yes');
                        alert(data);
                    }
                });

                if (!(this.value < 1)) {
                    product_total = parseFloat(price * this.value);
                    $('#product_total_price .price').html(currency + product_total.toFixed(2));
                }
            });
        });
    </script>

<?php
}
// We are going to hook this on priority 31, so that it would display below add to cart button.
add_action('woocommerce_single_product_summary', 'action_woocommerce_single_product_summary', 31, 0);