自己封装的一个简单的倒计时功能实例

function countDown(date,target,filter){

  var setTime = new Date(date).getTime(),
    timer = null;

  function core(){
    var nowTime = new Date().getTime(),
      leftTime = 0,
      d = 0,h = 0,m = 0,s = 0;

    ////////////////////////////
    //conditation @ doublue time
    if(filter.length){
      setTime = new Date();
      for(var i=0,l=filter.length;i<l;i++){
        setTime.setHours(filter[i]);
        setTime.setMinutes(0);
        setTime.setSeconds(0);
        if(nowTime < setTime.getTime()){
          break;
        }else if(i == filter.length-1){
          setTime.setDate(setTime.getDate()+1);
          setTime.setHours(filter[0]);
        }
        
      }
    }
    ////////////////////////////

    leftTime = Math.ceil((setTime - nowTime)/1000);
    if(nowTime <= setTime){
      d = ~~(leftTime/86400);
      h = ~~(leftTime%86400/3600);
      m = ~~(leftTime%86400%3600/60);
      s = ~~(leftTime%86400%3600%60);
      timer = setTimeout(core,1e3);
    }else{
      clearTimeout(timer);
      timer = null;
    }

    //here set out format
    target.innerHTML = 'd:'+d+' h:'+h+' m:'+m+' s:'+s;
    
  }
  core();
}

// 普通调用
countDown('2016/10/02/23:43',oDiv);
// 指定时间循环倒计时
countDown('2016/10/02/23:43',oDiv,[9,11,18]);