Вы можете создать переменную для хранения timerId
и очистить с помощью clearInterval
function pause() {
clearInterval(timerId);
}
var timerId;
var min = 0;
var sec = 59;
var isplay = true;
document.getElementById('pause').style.display = 'none';
function startTimer() {
var btton = document.getElementById('start').style.display = 'none';
document.getElementById('pause').style.display = 'inline';
timerId = setInterval(function () {
document.getElementById("timer").innerHTML = min + ":" + sec;
sec--;
if (sec == -1) {
min--;
sec = 59;
}
if (min == -1) {
clearTimeout();
}
if (sec < 10) {
sec = "0" + sec;
}
}, 1000);
}
function pause() {
clearInterval(timerId);
document.getElementById('start').style.display = 'inline';
document.getElementById('pause').style.display = 'none';
}
<div id="timer">
<div id="time">5:00</div>
</div>
<button id="start" onclick="return startTimer()">Start</button>
<button id='pause' onclick="pause()">Pause</button>