Question

我在php中的项目

我想创建一个倒数计时器，用于在有限的时间范围内询问问题，例如LMS 这里我使用了javascript倒计时器，但是当刷新页面时，javascript计时器被重置。

Answer 1

您可以将开始时间存储在php会话中。然后，每次加载页面时，您都可以使用javascript继续倒数计时器，例如

<?php
//on every page
session_start();

//when you start
$_SESSION['start_time'] = time();

然后在每一页上：

<script type="text/javascript">
    var startTime = <?php echo $_SESSION['start_time']; ?>;
    //calculate remaining time
</script>

您需要注意时区不同或客户端时钟错误的时间。也许您可以用秒计算剩余时间并在每个页面上将其打印到javascript中，但之后您可能会在高延迟连接等情况下进行查看。

Answer 2

尝试类似：

<?php
   session_start();

   //to reset the saved countdown
   if (!empty($_REQUEST['resetCountdown']))
   {
       unset($_SESSION['startTime']);
   }

   if (empty($_SESSION['startTime']))
   {
       $_SESSION['startTime'] = time();
   }

   //In seconds
   $startTime = time() - $_SESSION['startTime'];
?>
<script type="text/javascript">
var countdown = 60; //in seconds
var startTime = <?php echo $startTime; ?>;

startCountdown(startTime, countdown);

function startCountdown(startFrom, duration)
{
   //countdown implementation
}
</script>

Answer 3

您还可以将计时器存储在PHP中的会话变量中，以便在刷新页面时仍然保留时间。

Answer 4

试试这个

<script>
// Set the date we're counting down to
var countDownDate = new Date("Aug 1, 2017 12:00:00").getTime();

// Update the count down every 1 second
var x = setInterval(function() {

    // 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);

    // Output the result in an element with id="demo"

    document.getElementById("demo").innerHTML = days + "d " + hours + "h "
    + minutes + "m " + seconds + "s "; 


    // If the count down is over, write some text 
    if (distance < 0) {
        clearInterval(x);
        document.getElementById("demo").innerHTML = "EXPIRED";
    }
}, 1000);
</script>

并将其置于正文标记下。

<p id="demo"></p>

倒计时器

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