This is my code below:

function triggerTimer() {
    var myInt = window.setInterval(timerStart, 1000);
    setTimeout(removeInt, 4000);
}
function timerStart() {
    var timerValue = parseInt(document.getElementById('timer').innerHTML);
    if (timerValue > 0) {
        timerValue -= 1;
        document.getElementById('timer').innerHTML = '0' +timerValue.toString();
        console.log(timerValue);

    }
    else {
        var correct = document.getElementById(`c${row}`).innerHTML;
        multiplechoice.innerHTML = '<p>The correct answer is <span style="color: white;" id=`c${row}`>'+correct+'</span><br><button onclick="submitEntry();">Next Question</button></p>';
    }
}
function removeInt() {
    if(clearInterval(myInt)) {console.log('success')} else {console.log('fail')}
}

Above this code is a timer that decreases every time timerStart function is called. The problem is that the timer stops the first time removeInt function is triggered, even though it logs 'fail'.

But the second time timerStart is triggered, the time still decreases, but when removeInt is called, the interval isn't cleared.