实现时间倒计时
<script language="javascript">
function Change(HourSurplus,MinuteSurplus,SecondSurplus)
{

SecondSurplus = SecondSurplus - 1;
if (SecondSurplus<0)
{
SecondSurplus=60+SecondSurplus;
MinuteSurplus=MinuteSurplus-1;
}
if (MinuteSurplus<0)
{
MinuteSurplus=60+MinuteSurplus;
HourSurplus=HourSurplus-1;
}

document.getElementById("asd").innerHTML=""+ HourSurplus +":"+ MinuteSurplus +":"+ SecondSurplus +"";
setTimeout(function() {
Change(HourSurplus,MinuteSurplus,SecondSurplus);
},1000);
}

</script>
<!-- innerHTML 属性设置或返回表格行的开始和结束标签之间的 HTML。 -->
<span id="asd">11111</span>
<script language="javascript">
Change(1,59,59);
</script>