用JS写一个倒计时，从页面获取的数据。见详情

Question

<div id="exam-time"class="ub ub-ac ufr">

                <span id="exam-countdown" >
                    结束倒计时：10:00:00                </span>
                
                秒从59到0
                分钟-1，
                分钟-60小时-1，
                
                小菜鸟谢谢大家了！

Answer 1

demo