<SCRIPT LANGUAGE="JavaScript">
<!--
var maxtime = 60*60 //一个小时，按秒计算，自己调整!
function CountDown(){
if(maxtime>=0){
minutes = Math.floor(maxtime/60);
seconds = Math.floor(maxtime%60);
msg = "距离结束还有"+minutes+"分"+seconds+"秒";
document.all["timer"].innerHTML=msg;
if(maxtime == 5*60) alert('注意，还有5分钟!');
--maxtime;
}
else{
clearInterval(timer);
alert("时间到，结束!");
}
}
timer = setInterval("CountDown()",1000);
//-->
</SCRIPT>
<div id="timer" style="color:red"></div>
