JS实现获取时间和设置倒计时代码分享

<script type="text/javascript">
 var timeBox = document.querySelector("#time"); function countdown(){
 var nowTime = new Date(); var targetTime = new Date("2018/2/27 15:44:15"); var spanTime = targetTime-nowTime; if(spanTime <=0){
 timeBox.innerHTML="立即抢购";
 clearInterval(countdown);
 }else{ var hours = Math.floor(spanTime/(1000*60*60));
 spanTime-=hours*60*60*1000; var minute = Math.floor(spanTime/(1000*60));
 spanTime-=minute*60*1000; var second = Math.floor(spanTime/1000);
 hours<10 ? hours='0'+hours : hours;
 minute<10 ? minute='0'+minute : minute;
 second<10 ? second='0'+second : second;
 timeBox.innerHTML=hours+':'+minute+':'+second;
 }

 } var timer = window.setInterval(countdown,1000); </script>

<script type="text/javascript">
 var timeBox = document.querySelector("#time"); function countdown(){
 var date = new Date(); var hours = date.getHours(); var minute = date.getMinutes(); var second = date.getSeconds();
 hours =checkTime(hours);
 minute =checkTime(minute);
 second =checkTime(second);
 timeBox.innerHTML = hours+':'+minute+':'+second;
 } // 检测时间数字是否小于10，在小于10的数字前加一个‘0’
 function checkTime(i){
 i<10 ? i="0"+i :i; return i;
 } var timer = window.setInterval(countdown,1000); </script>