代码很简单，直接上代码了，大家可以复制下面的代码保存成HTML文件运行看效果
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head></head>
<body>
<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>
<span id="asd">11111</span>
<script language="javascript">
Change(1,59,59);
</script>
</body>
</html>