下面给出一个效果图，我今天要说的就是实现下图这种多个倒计时

很多时候我们做只有一个倒计时的情况比较多，比较简单只需要一个定时器setInterval，算出来赋赋值就好，

但是需要多个倒计时的时候我们就要考虑把倒计时封装成通用的方法了

拿我自己的vue项目举个例

    <!-- template -->
    <div v-for="(item,index) in list" :key="index" class="act_item">
        <h1>{{ item.title }}</h1>
        <img :src="item.pic" alt="">
        <div class="act_info">
            <h2><span>{{ item.count }}</span>个视频</h2>
            <div class="time">倒计时：{{ item.djs }}</div>
            <div class="clear"></div>
        </div>
    </div>

<script>
function InitTime(endtime){
    var dd,hh,mm,ss = null;
    var time = parseInt(endtime) - new Date().getTime();
    if(time<=0){
        return '结束'
    }else{
        dd = Math.floor(time / 60 / 60 / 24);
        hh = Math.floor((time / 60 / 60) % 24);
        mm = Math.floor((time / 60) % 60);
        ss = Math.floor(time  % 60);
        var str = dd+"天"+hh+"小时"+mm+"分"+ss+"秒";
        return str;
    }
}
export default {
    data () {
	return {
            active: 'tab-container1',
            pinkFont:true,
            // 上拉刷新、下拉加载
            allLoaded: false, //如果为true,禁止上拉刷新
            autoFill: false, //取消自动填充，
            list: [],
    	}
      },
    created() {
        var ssss = [
            {"title": "小心愿，大梦想","pic":"../../assets/img/new/act1.jpg","count":"34","time":"1525293470350"},
            {"title": "杭州国际时装周童模招募","pic":"../../assets/img/new/act2.jpg","count":"36","time":"1525293470350"},
            {"title": "怪兽bobo全线代言火爆杭城的联名秀招募童模啦！","pic":"../../assets/img/new/act3.jpg","count":"74","time":"1529253270350"},
            {"title": "汉风唐韵 、别","pic":"../../assets/img/new/act2.jpg","count":"266","time":"1525753270350"},
            {"title": "听说你们想和明星超模同台“PK”？","pic":"../../assets/img/new/act1.jpg","count":"97","time":"1525253270450"},
        ];
        ssss.map( (obj,index)=>{
            this.$set(
                obj,"djs",InitTime(obj.time)
            );
        })
        this.list = ssss;
    },
    mounted() {
        setInterval( ()=> {
            for (var key in this.list) {
                var aaa = parseInt( this.list[key]["time"] );
                var bbb = new Date().getTime();
                var rightTime = aaa - bbb;
                if (rightTime > 0) {
                    var dd = Math.floor(rightTime / 1000 / 60 / 60 / 24);
                    var hh = Math.floor((rightTime / 1000 / 60 / 60) % 24);
                    var mm = Math.floor((rightTime / 1000 / 60) % 60);
                    var ss = Math.floor((rightTime / 1000) % 60);
                }
                this.list[key]["djs"] = dd + "天" + hh + "小时" + mm + "分" + ss + "秒";
            }
        }, 1000);

    },
    methods: {

    }
}
</script>

需要注意的是那个标红的代码，在一个对象已经有了的情况下，假如此时object里没有djs这个元素，直接object.djs = "要赋的值"这样的做法是不正确的，可能会赋值成功，但是会出现很多奇怪的问题，推荐用

this.$set(object,'djs','要赋的值');