js定时器倒计时

function CountDown() {if (maxtime >= 1) {                     minutes = Math.floor(maxtime / 60);                     seconds = Math.floor(maxtime % 60);                     msg = "距离结束还有" + minutes + "分" + seconds + "秒";                   //  console.log(msg)                   //  if (maxtime == 5 * 60)alert("还剩5分钟");                         --maxtime;                 } else{                 maxtime = maxtime + 10*timecount + 5;                 timecount ++;                 if(maxtime==0){                 maxtime =5;                 }                 dtime = dtime + 10                 console.log(dtime);                    // Avatar.push(['track', ['stay', 'mainpage', '', {duration:dtime+1}, 0]])                 }             }   timer = setInterval("CountDown()", 1000);