javascript - Uncaught TypeError: Cannot set property 'textContent' of null in Countdown Timer within Laravel

one text

I am running a timer in javascript for a php / laravel appication. in the console, I get a running error every second as the timer is running. I am not sure how to make the error go away. It does not effect the operation of the application as the timer does work. I also tried wrapping the code in a DOMContentLoaded function which had no effect. Can anyone let me know what I might have missed. Thank you. Here is the js code:

document.addEventListener("DOMContentLoaded", function() {

    function startTimer(duration, display) {
        let timer = duration, minutes, seconds;
        setInterval(function () {
            minutes = parseInt(timer / 60, 10);
            seconds = parseInt(timer % 60, 10);

            minutes = minutes < 10 ? "0" + minutes : minutes;
            seconds = seconds < 10 ? "0" + seconds : seconds;

            display.textContent = minutes + ":" + seconds;

            if (--timer < 0) {
                timer = duration;
                alert('Your time has expired');
                window.location.href="/student/exam";
            }
        }, 1000);
    }

    window.onload = function () {
        let sixtyMinutes = 60 * 60,
            display = document.querySelector('#time');
        startTimer(sixtyMinutes, display);
    };
});

And where I am calling the function inside the php file:

<div class="card-body">
                    <div class="row">
                       <div class="col-sm-4">
                           <h3>Time: 1 Hour</h3>
                       </div>
                       <div class="col-sm-4">
                            <h3 class="text-center">Timer : <span id="time" class="">60:00</span></h3>
                       </div>
                       <div class="col-sm-4">
                           <h3 class="text-right">Status: Pending</h3>
                       </div>
                    </div>
                </div>
                <!-- /.card-body -->

The line in question in the js code is:

display.textContent = minutes + ":" + seconds;

Again, any help appreciated. Thank you.

Edit:: Image of error:

Uncaught TypeError: display is null
    startTimer http://lionsfieldtest.test/assets/js/custom.js:94
custom.js:94:13