javascript - 倒数计时器启动和停止

Question

我创建了在线考试系统。

我的问题：我点击申请按钮比倒计时器开始和有时浏览器页面关闭后，我点击相同的考试名称，然后倒数计时器继续，不开始开始。下面的截图

screenshot-1

screenshot -2

查看：

<h2><p style="float: right" id="countdown"></p></h2> 

<a href="<?php echo base_url(); ?>student/Examinations/apply_examinations/<?php echo $value['examination_test_id']; ?>" class="btn btn-primary" id="apply" onclick="resetCountdownInLocalStorage();">Apply</a> 

    <script> 
     $(document).ready(function() { 
    $examination_test_id = $("#examination_test_id").val(); 
      $time_limit = $("#time_limit").val(); 
      var d = new Date($time_limit); 
      var hours = d.getHours(); 
      var minute = d.getMinutes(); 
      var minutes = hours * 60 + minute; 
      var seconds = 60 * minutes; 

      if (typeof (Storage) !== "undefined") { 
       if (sessionStorage.seconds) { 
        seconds = sessionStorage.seconds; 
       } 
      } 
      function secondPassed() { 
       var hours = Math.floor(seconds/3600); 
       var minutes = Math.floor((seconds - (hours * 3600))/60); 
       // var remainingSeconds = seconds - (hours * 3600) - (minutes * 60); 
       var remainingSeconds = seconds % 60; 

       if (remainingSeconds < 10) { 
        remainingSeconds = "0" + remainingSeconds; 
       } 
       if (minutes < 10) { 
        minutes = "0" + minutes; 
       } 

       if (typeof (Storage) !== "undefined") { 
        sessionStorage.setItem("seconds", seconds); 
       } 

       document.getElementById('countdown').innerHTML = hours + ":" + minutes + ":" + remainingSeconds; 

       if (seconds == 0) { 
        clearInterval(myVar); 
        document.getElementById('countdown').innerHTML = alert('Timeout'); 
        window.location.href = base_url + "student/Examinations/check_answer/" + $examination_test_id; 

        if (typeof (Storage) !== "undefined") { 
         sessionStorage.removeItem("seconds"); 
        } 
       } else { 
        seconds--; 
       } 
      } 
      var myVar = setInterval(secondPassed, 1000); 
     }); 

function resetCountdownInLocalStorage() { 
     sessionStorage.removeItem("seconds"); 
    } 
    </script> 

Answer 1

它可能会依赖于浏览器，根据该link

浏览的寿命上下文可能与实际用户代理进程本身的生存期无关，因为用户代理可能在重新启动后支持 恢复会话。

您可能必须清理选项卡上的会话stroage close我认为。