题解 | #倒计时#

		function second(second) {
            let obj = {
                day: Math.floor(second / 60 / 60 / 24),
                hour: Math.floor(second / 60 / 60 % 24),
                min: Math.floor(second / 60 % 60),
                second: second % 60
            }

            return obj;
        }

        function render(data) {
            let wrapper = document.querySelector('#jsCountdown');
            for (let i in data) {
                data[i] = data[i] > 9 ? data[i] : '0' + data[i];
            }

            if (data.day === '00') {
                wrapper.children[0].classList.add('hide');
            } else {
                wrapper.children[0].innerHTML = data.day + '天';
            }

            wrapper.children[1].innerHTML = data.hour + ':';
            wrapper.children[2].innerHTML = data.min + ':';
            wrapper.children[3].innerHTML = data.second;
        }