详解jquery实现倒计时小应用

<p id="shop_rec">
  <ul class="cf">
    <li>
      <img src="image/goods.jpg" alt="小米 Note 顶配版" />
      <p>
        <h5>小米 Note 顶配版</h5>
        <p>全网通 香槟金 移动联通<br />双4G手机 双卡双待</p>
        <em>¥2998<i>起</i></em>
        <span class="time" data-starttime="1445982375" data-endtime="1446350400"></span>
      </p>
    </li>
    <li>
      <img src="image/goods.jpg" alt="小米 Note 顶配版" />
      <p>
        <h5>小米 Note 顶配版</h5>
        <p>全网通 香槟金 移动联通<br />双4G手机 双卡双待</p>
        <em>¥2998<i>起</i></em>
        <span class="time" data-starttime="1445912375" data-endtime="1436350400"></span>
      </p>
    </li>
  </ul>
</p>

$(function(){
  var abj = $("#shop_rec"),
    timeObj = abj.find('.time');
  var starttime = timeObj.data('starttime');

  // 定时器函数
  function actionDo(){
    return setInterval(function(){
      timeObj.each(function(index, el) {
        var t = $(this),
          surplusTime = t.data('endtime') -starttime;
        if (surplusTime <= 0) {
          t.html("活动已经开始");
        } else{
          var year = surplusTime/(24*60*60*365),
            showYear = parseInt(year),
            month = (year-showYear)*12,
            showMonth = parseInt(month),
            day = (month-showMonth)*30,
            showDay = parseInt(day),
            hour = (day-showDay)*24,
            showHour = parseInt(hour),
            minute = (hour-showHour)*60,
            showMinute = parseInt(minute),
            seconds = (minute-showMinute)*60,
            showSeconds = parseInt(seconds);
          t.html("");
          if (showYear>0) {
            t.append("<span>"+showYear+"年</span>")
          };
          if (showMonth>0) {
            t.append("<span>"+showMonth+"月</span>")
          };
          if (showDay>0) {
            t.append("<span>"+showDay+"天</span>")
          };
          if (showHour>=0) {
            t.append("<span>"+showHour+"小时</span>")
          };
          if (showMinute>=0) {
            t.append("<span>"+showMinute+"分钟</span>")
          };
          if (showSeconds>=0) {
            t.append("<span>"+showSeconds+"秒</span>")
          };
        };
      });
      starttime++;
    },1000); // 设定执行或延时时间
  };
  // 执行它
  actionDo();
});