javascript - 카운트다운

1. html

<div id="timer"></div>

2. javascript

function updateTimer() {
        const future = Date.parse("2023/08/19 00:00:00");
        const now = new Date();
        const diff = future - now;

        const days = Math.floor(diff / (1000 * 60 * 60 * 24));
        const hours = Math.floor(diff / (1000 * 60 * 60));
        const mins = Math.floor(diff / (1000 * 60));
        const secs = Math.floor(diff / 1000);

        const d = days;
        const h = hours - days * 24;
        const m = mins - hours * 60;
        const s = secs - mins * 60;

        document.getElementById("timer")
            .innerHTML =
            '<div>' + '<span>DAYS</span>' + d + '</div>' +
            '<div>' + '<span>HOURS</span>' + h + '</div>' +
            '<div>' + '<span>MINUTES</span>' + m + '</div>' +
            '<div>' + '<span>SECONDS</span>' + s + '</div>'
    }

    setInterval(updateTimer, 1000);