Question

我有这个js代码。它工作但我注意到我得到这样的错误。＆＃34; TypeError：document.getElementById（...）为null＆＃34; 而且我注意到在firebug中计数错误的错误。所以我假设它是继续前进的for循环。你能看一下下面的代码并告诉我它有什么问题吗？

＆＃13;

<script>
$( document ).ready(function() {

    //Create object with the list of due dates
    //The 'name' will correspond to the field ID to populate the results
    var dueDates = {
        'date1':'2017-04-17 09:55:18',
        'date2':'2017-05-17 09:55:18',
        'date3':'2017-06-17 09:55:18'
    };

    var timer = setInterval(function() {
        //Instantiate variables
        var dueDate, distance, days, hours, minutes, seconds, output;
        //Set flag to repeat function
        var repeat = false;
        // Get todays date and time
        var now = new Date().getTime();
        //Iterate through the due dates
        for (var dueDateId in dueDates) {
            //Get the due date for this record
            dueDate = new Date(dueDates[dueDateId]);
            // Find the distance between now an the due date
            distance = dueDate - now;
            // Time calculations for days, hours, minutes and seconds
            days    = Math.floor(distance  / (1000 * 60 * 60 * 24));
            hours   = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
            minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
            seconds = Math.floor((distance % (1000 * 60)) / 1000);
            //Determine the output and populate the corresponding field
            output = "OVERDUE";
            if (distance > 0)
            {
                output = days + "d " + hours + "h " + minutes + "m " + seconds + "s";
                repeat = true; //If any record is not expired, set flag to repeat
            }
            document.getElementById(dueDateId).innerHTML = output;
            //If flag to repeat is false, clear event
            if(!repeat)
            {
                clearInterval(timer);
            }
        }
    }, 1000);
});
</script>

＆＃13;

<div id="date1"></div>
<div id="date2"></div>
<div id="date3"></div>

＆＃13;

Answer 1

您的第一个截止日期是未来，因此距离是正数，因此 repeat 在循环的第一次迭代中设置为true。由于它在循环中永远不再变为false，因此clearInterval函数不会在任何for循环迭代中执行。因此，1秒后将再次调用setInterval回调，并重复相同的逻辑...

这个javascript代码有什么问题？它不停地循环

1 个答案: