Front: Countdown to send text messages

// h5部分
<input type="button" value="获取验证码" class="zdc">

// js部分
let $zdc = $('.zdc');
    let is_send = 0;
    $zdc.click(function () {
        if (is_send === 0) {
            $.ajax({
                url: "http://api.jx3blog.cn:8000/user/sms/",
                method: 'post',
                data: {
                    "phone": $('#id_phone').text(),
                },
                success: function (res) {
                    is_send = 1;
                    let sms_interval_time = 60;
                    let codetime = setInterval(clock, 1000);

                    function clock() {
                        sms_interval_time -= 1;
                        $zdc.val(`${sms_interval_time}秒后再次获取`);
                        if (sms_interval_time <= 0) {
                            clearInterval(codetime);
                            $zdc.val('获取验证码');
                            is_send = 0;
                        }
                    }
                }
            })
        }
    });