jquery simple countdown implementation method

var intDiff = parseInt(60); //倒计时总秒数量
function timer(intDiff) {
  window.setInterval(function () {
    var day = 0,
      hour = 0,
      minute = 0,
      second = 0; //时间默认值
    if (intDiff > 0) {
      day = Math.floor(intDiff / (60 * 60 * 24));
      hour = Math.floor(intDiff / (60 * 60)) - (day * 24);
      minute = Math.floor(intDiff / 60) - (day * 24 * 60) - (hour * 60);
      second = Math.floor(intDiff) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60);
    }
    if (minute <= 9) minute = &#39;0&#39; + minute;
    if (second <= 9) second = &#39;0&#39; + second;
    $(&#39;#day_show&#39;).html(day + "天");
    $(&#39;#hour_show&#39;).html(&#39;&#39; + hour + &#39;时&#39;);
    $(&#39;#minute_show&#39;).html(&#39;&#39; + minute + &#39;分&#39;);
    $(&#39;#second_show&#39;).html(&#39;&#39; + second + &#39;秒&#39;);
    intDiff--;
  }, 1000);
}
$(function () {
  timer(intDiff);
});