php - how to apply the modified final cost on the checkout page via ajax?

one text

There is a task: to fasten the button on the checkout page by pressing which the discount for the total amount should be applied. Greetings to all! There is a task: to fasten the button on the checkout page by pressing which the discount for the total amount should be applied.

jQuery(document).ready(function($) {
    $("#discount_btn").click(function() {
        action = "setdiscount";
        $.ajax({
            type: "POST",
            dataType: "json",
            url: wc_checkout_params.ajax_url,
            data: {
                "action": action,
            },
            success: function(data) {
                $(document.body).trigger("update_checkout");
                console.log(data);
            }
        });
    })
})

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