js实现时间段的倒计时显示

$(document).ready(function(){

 var SysSecond = parseInt($('#sec_left').text());
 var InterValObj = window.setInterval(SetRemainTime, 1000);
 function SetRemainTime(){
  if (SysSecond > 0) {
   SysSecond = SysSecond - 1;
   var second = Math.floor(SysSecond % 60);
   var minite = Math.floor((SysSecond / 60) % 60);
   var hour = Math.floor((SysSecond / 3600) % 24);
   var day = Math.floor((SysSecond / 3600) / 24);
       $("#time").html(day + "天" + hour + "小时" + minite + "分" + second + "秒");
     }else{
   window.clearInterval(InterValObj);
  }
 }