javascript - jQuery倒数计时器，历时数秒

我想创建一个jquery倒数计时器，我尝试了以下代码，但是它不起作用。我该怎么办？

演示: https://jsfiddle.net/tbosn210/

var interval = setInterval(function() {

    var timer2 = $("5:01");
    var timer = timer2.split(':');
    //by parsing integer, I avoid all extra string processing
    var minutes = parseInt(timer[0],10);
    var seconds = parseInt(timer[1],10);
    --seconds;
    minutes = (seconds < 0) ? --minutes : minutes;
    if (minutes < 0) clearInterval(interval);
    seconds = (seconds < 0) ? 59 : seconds;
    seconds = (seconds < 10) ? '0' + seconds : seconds;
    //minutes = (minutes < 10) ?  minutes : minutes;
    $('.countdown').html(minutes + ':' + seconds);
}, 1000);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="countdown"></div>

最佳答案

将您的timer2声明移出setInterval函数，在执行结束时将新的时间值分配给timer2以继续。

工作片段:

var timer2 = "5:01";
var interval = setInterval(function() {


  var timer = timer2.split(':');
  //by parsing integer, I avoid all extra string processing
  var minutes = parseInt(timer[0], 10);
  var seconds = parseInt(timer[1], 10);
  --seconds;
  minutes = (seconds < 0) ? --minutes : minutes;
  if (minutes < 0) clearInterval(interval);
  seconds = (seconds < 0) ? 59 : seconds;
  seconds = (seconds < 10) ? '0' + seconds : seconds;
  //minutes = (minutes < 10) ?  minutes : minutes;
  $('.countdown').html(minutes + ':' + seconds);
  timer2 = minutes + ':' + seconds;
}, 1000);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="countdown"></div>