How to exam wise countdown timer start
<p>I create online examination system and i create different exam and different time assign ,i click any exam accroding to countdown timer start, 
see below screenshot </p>

<p>ScreenShot-1</p>

<p><a href="https://i.stack.imgur.com/aHLVm.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aHLVm.jpg" alt="enter image description here"></a></p>

<p>Screenshot-2</p>

<p><a href="https://i.stack.imgur.com/7WmBl.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7WmBl.jpg" alt="enter image description here"></a></p>

<p><strong>View:</strong></p>

<pre><code>&lt;input type="hidden" name="time_limit" id="time_limit" value="&lt;?php echo $examination_test_result['time_limit']; ?&gt;"&gt;

&lt;div class="box-body"&gt;
    &lt;h2&gt;&lt;p style="float: right" id="countdown"&gt;&lt;/p&gt;&lt;/h2&gt;

&lt;script&gt;

     $time_limit = $("#time_limit").val();
        var d = new Date($time_limit);
        var hours = d.getHours();
        var minutes = d.getMinutes();
        var seconds = 60 * minutes;

        if (typeof (Storage) !== "undefined") {      //checks if localStorage is enabled
            if (localStorage.seconds) {                       //checks if seconds are saved to localstorage
                seconds = localStorage.seconds;
            }
        }
        function secondPassed() {
            var minutes = Math.round((seconds - 30) / 60);
            var hours = Math.round((minutes) / 60);
            var remainingSeconds = seconds % 60;
            if (remainingSeconds &lt; 10) {
                remainingSeconds = "0" + remainingSeconds;
            }

            if (typeof (Storage) !== "undefined") {
                localStorage.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";

                if (typeof (Storage) !== "undefined") {
                    localStorage.removeItem("seconds");
                }
            } else {
                seconds--;
            }

        }
        var myVar = setInterval(secondPassed, 1000);
    });
&lt;/script&gt;
</code></pre>

<p>MY Question: I click different exam and examwise countdown timer start.             but i have problem i click any exam and countdown timer continue</p>