日期倒计时

以下为js代码段

  setInterval(function () {
        //new  一个日期实例
        var date = new Date()
        var nowYear = date.getFullYear()
        //获得年份
        date.setFullYear(nowYear + 1,0,1)
        date.setHours(0,0,0,0)
        var desTime = date.valueOf()
        var nowTime = new Date()
        //计算时间差
        var time = desTime - nowTime
        var days = Math.floor(time / (1000 * 60 * 60 * 24))
        var hours = time % (1000 * 60 * 60 * 24) / (1000 * 60 * 60)
        var hours = Math.floor(hours)
        var minutes = (time % (1000 * 60 * 60)) / (1000 * 60)
        var minutes = Math.floor(minutes)
        var seconds = (time % (1000 * 60)) / 1000
        var seconds = Math.floor(seconds)
        var span = document.getElementById("timer")
        span.innerHTML = "<p>" + nowYear + "</p>" + "年还剩" +days +"天" +hours+ "小时"+minutes+ "分钟"+seconds+"秒"
    },1000)