jquery timer, javascript countdown (타이머 예제)

function dailyMissionTimer(duration) {
    
    var timer = duration * 3600;
    var hours, minutes, seconds;
    
    var interval = setInterval(function(){
        hours	= parseInt(timer / 3600, 10);
        minutes = parseInt(timer / 60 % 60, 10);
        seconds = parseInt(timer % 60, 10);
		
        hours 	= hours < 10 ? "0" + hours : hours;
        minutes = minutes < 10 ? "0" + minutes : minutes;
        seconds = seconds < 10 ? "0" + seconds : seconds;
		
        $('#time-hour').text(hours);
        $('#time-min').text(minutes);
        $('#time-sec').text(seconds);

        if (--timer < 0) {
            timer = 0;
            clearInterval(interval);
        }
    }, 1000);
}

dailyMissionTimer(24);	// hour base

<span id="time-hour"></span>
<span id="time-min"></span>
<span id="time-sec"></span>

function countdown( elementName, minutes, seconds )
{
    var element, endTime, hours, mins, msLeft, time;

    function twoDigits( n )
    {
        return (n <= 9 ? "0" + n : n);
    }

    function updateTimer()
    {
        msLeft = endTime - (+new Date);
        if ( msLeft < 1000 ) {
            element.innerHTML = "countdown's over!";
        } else {
            time = new Date( msLeft );
            hours = time.getUTCHours();
            mins = time.getUTCMinutes();
            element.innerHTML = (hours ? hours + ':' + twoDigits( mins ) : mins) + ':' + twoDigits( time.getUTCSeconds() );
            setTimeout( updateTimer, time.getUTCMilliseconds() + 500 );
        }
    }

    element = document.getElementById( elementName );
    endTime = (+new Date) + 1000 * (60*minutes + seconds) + 500;
    updateTimer();
}

countdown( "countdown", 1, 5 );
countdown( "countdown2", 100, 0 );

<div id="countdown"></div>
<div id="countdown2"></div>

div {
    color: #1B232F;
    font-family: Verdana, Arial, sans-serif;
    font-size: 18px;
    font-weight: bold;
    text-decoration: none;
}