var tt=setInterval(function(){
    document.body.innerHTML='';
    let target=new Date('2017/11/4/23:59');
    let hh=target-new Date();
    let cha=Math.floor(hh/1000);
    let date=Math.floor(cha/86400);
    cha%=86400;
    let hour=Math.floor(cha/3600);
    cha%=3600;
    let minute=Math.floor(cha/60);
    cha%=60
    let second=cha;
    if(hh<=0){
        document.write('it is time to contribute my resume');
        clearInterval(tt);
    }else{
       document.write(`还剩${date}天${hour}小时${minute}分钟${second}秒`);
    }
},1000);