倒计时（自留）

<p id="pobj"><p>
<script>
function time(){
        //目标时间
        var targetDate=new Date("2019/1/1")

        //获取当前时间
        var now = new Date()

        //目标时间和当前时间相差的毫秒
        var millon =targetDate.getTime() - now.getTime()
        var seconds =millon/1000

        //一天的毫秒数=24*60*60*1000
        var days = parseInt(seconds/(24*60*60))

        //剩余的小时=(millon - days *24*60*60*1000)/(60*60*1000)
        var hours =parseInt(seconds%(24*60*60)/3600)

     
        var minutes = parseInt(seconds%3600/60)
     
        var ss =parseInt(seconds%60)
     
        var pobj =document.getElementById("pobj")
        pobj.innerHTML="离2019年元旦还剩"+days+"天"+hours+"小时"+minutes+"分钟"+ss+"秒"
    }
    setInterval("time()",1000)
<script>