JavaScript setIntervall只运行一次

Question

<script> 

    function countdown(){ 
     jQuery(document).ready(function($){ 
      var countdown_html = $('.countdown').clone(); 
      var countDownDate = new Date("Apr 23, 2017 19:37:25").getTime(); 


      // Update the count down every 1 second 

      // Get todays date and time 
      var now = new Date().getTime(); 

      // Find the distance between now an the count down date 
      var distance = countDownDate - now; 

      // Time calculations for days, hours, minutes and seconds 
      var days = Math.floor(distance/(1000 * 60 * 60 * 24)); 
      var hours = Math.floor((distance % (1000 * 60 * 60 * 24))/(1000 * 60 * 60)); 
      var minutes = Math.floor((distance % (1000 * 60 * 60))/(1000 * 60)); 
      var seconds = Math.floor((distance % (1000 * 60))/1000); 

      $('.num.days', countdown_html).text(days); 
      $('.num.hours', countdown_html).text(hours); 
      $('.num.minutes', countdown_html).text(minutes); 
      $('.num.seconds', countdown_html).text(seconds); 

      $('.countdown').countdown({until: <?php echo $date['to'] ?>, layout: countdown_html.html() }); 

     }); 
    } 
var run = setInterval(countdown,1000); 

</script> 

此代码仅在1秒后执行一次倒计数功能。我试图实现一个简单的倒数计时器，扩展了一个不兼容的wordpress插件。我是一个JavaScript初学者，以上都是100％复制&粘贴，但它都可以工作，除了自动调用函数。

Answer 1

由于您的所有代码都被封装在jQuery(document).ready()方法中，所以只有在文档准备好并且根据定义只能发生一次时，它才会执行。

Answer 2

移动你的初始化函数如下：

<script> 
    jQuery(document).ready(function($){ 
     function countdown(){ 

      var countdown_html = $('.countdown').clone(); 
      var countDownDate = new Date("Apr 23, 2017 19:37:25").getTime(); 


      // Update the count down every 1 second 

      // Get todays date and time 
      var now = new Date().getTime(); 

      // Find the distance between now an the count down date 
      var distance = countDownDate - now; 

      // Time calculations for days, hours, minutes and seconds 
      var days = Math.floor(distance/(1000 * 60 * 60 * 24)); 
      var hours = Math.floor((distance % (1000 * 60 * 60 * 24))/(1000 * 60 * 60)); 
      var minutes = Math.floor((distance % (1000 * 60 * 60))/(1000 * 60)); 
      var seconds = Math.floor((distance % (1000 * 60))/1000); 

      $('.num.days', countdown_html).text(days); 
      $('.num.hours', countdown_html).text(hours); 
      $('.num.minutes', countdown_html).text(minutes); 
      $('.num.seconds', countdown_html).text(seconds); 

      $('.countdown').countdown({until: <?php echo $date['to'] ?>, layout: countdown_html.html() }); 


    } 
var run = setInterval(countdown,1000); 
    }); 
</script> 

jQuery(document).ready只调用一次