How to create an accurate timer in javascript?

Question

I need to create a simple but accurate timer.

This is my code:

var seconds = 0;
setInterval(function() {
timer.innerHTML = seconds++;
}, 1000);
         


        

Answer 1

This is an basic implementation of a simple timer. note: .timer is the class where the timer is to be shown, and done function is your implementation which will trigger after timers completion

function TIMER() {
        var fiveMinutes = 60 * 5,
        display = document.querySelector('.timer');

        startTimer(fiveMinutes, display);
    }
    var myInterval;
    function startTimer(duration, display) {
        var timer = duration, minutes, seconds;

        myInterval = 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) {
                clearInterval(myInterval);
                doneFunction();
            }
        }, 1000);
    }