不依赖客户端时间的倒计时js程序

 var startTime = new Date("$!time");
var time=$!paper.time;
var EndTime=startTime.getTime()+time*60*1000;
var intervalTime=startTime.getTime();
function GetRTime(){
var nMS=EndTime-intervalTime;
var nH=Math.floor(nMS/(1000*60*60)) % 24;
var nM=Math.floor(nMS/(1000*60)) % 60;
var nS=Math.floor(nMS/1000) % 60;
document.getElementById("RemainH").innerHTML=nH;
document.getElementById("RemainM").innerHTML=nM;
document.getElementById("RemainS").innerHTML=nS;
intervalTime=intervalTime+1000;
if(nH==0&nM==5&nS==0)
{
alert("还有最后五分钟！");
}
if(nH==0&nM==0&nS==0){
var paperForm=document.getElementById("ListForm");
paperForm.submit();
alert("考试时间到，试卷自动提交！");
}
setTimeout("GetRTime()",1000);
}
window.onload=GetRTime;