用js写倒计时

来源：互联网发布：星星知我心1983 编辑：程序博客网时间：2024/06/04 17:43

写倒计时，首先我们需要想到的是要设定时间和获取当前时间，然后两者相减就可以。但是这里需要注意的是天、时、分、秒的换算，时分秒为单数时，前面要加零占位。

方法一：

<body>   <div id="times_wrap" class="time_num">       <p>距离结束时间：</p>       <div class="time_w">           <b id="times_d" class="time"> </b>天           <b id="times_h" class="time"> </b>时           <b id="times_m" class="time"> </b>分           <b id="times_s" class="time"> </b>秒       </div>   </div></body>

<script type="text/javascript">   var times = setTimeout("show_time()",1000);   var time_wrap = document.getElementById("times_wrap");   var time_d = document.getElementById("times_d");   var time_h = document.getElementById("times_h");   var time_m = document.getElementById("times_m");   var time_s = document.getElementById("times_s");      var time_end = new Date("2016/12/28 16:14:00");  // 设定结束时间   time_end = time_end.getTime();      function show_time(){       var time_now = new Date();  // 获取当前时间        time_now = time_now.getTime();       var time_distance = time_end - time_now;  // 结束时间减去当前时间        var int_day, int_hour, int_minute, int_second;       if(time_distance >= 0){           // 天时分秒换算           int_day = Math.floor(time_distance/86400000);           time_distance -= int_day * 86400000;           int_hour = Math.floor(time_distance/3600000);           time_distance -= int_hour * 3600000;           int_minute = Math.floor(time_distance/60000);           time_distance -= int_minute * 60000;           int_second = Math.floor(time_distance/1000);         // 时分秒为单数时、前面加零占位           if(int_hour < 10)           int_hour = "0" + int_hour;           if(int_minute < 10)           int_minute = "0" + int_minute;           if(int_second < 10)           int_second = "0" + int_second;         // 显示时间            time_d.innerHTML = int_day;           time_h.innerHTML = int_hour;           time_m.innerHTML = int_minute;           time_s.innerHTML = int_second;                      setTimeout("show_time()",1000);       }else{         alert("停止");           clearTimeout(times)       }   }</script>

也可以用另外一种思路来写：（为了简便，就用a和b来写了=。=）

<p id="p1">0:01:03</p><p id="p2"></p>

<script>    var day_time=document.getElementById("p1");    var new_time=document.getElementById("p2");    var a=day_time.innerHTML;    var b=a.split(":");    function time() {        b[2]--;        if(b[2]<10){            b[2]="0"+b[2];            if(b[2]==0&&b[1]>0){//秒                b[2]=59;                b[1]=b[1]-1;                if(b[1]<10){                    b[1]="0"+b[1];}                }            }        if(b[1]==0&&b[0]>0){//分            b[1]=59;            b[0]=b[0]-1;        }        if(b[0]==0&&b[1]==0&&b[2]==0){//时            clearInterval(tt);        }        new_time.innerHTML=b[0]+":"+b[1]+":"+b[2];    }    var tt=setInterval(time,1000);</script>

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