script.js

let hour = 0;
let minute = 0;
let second = 0;
let time;
let isStopped = false; // Add this line

function startTimer() {
    isStopped = false;
    document.getElementById("start").setAttribute("disabled","true");
    time = setInterval(() => { timer(); }, 1000);


}



function stopTimer() {
  if(isStopped) { // Add this condition
    return;
}
    isStopped = true; // Set isStopped to true when the timer is stopped
    document.getElementById("start").removeAttribute("disabled");
    clearInterval(time);
    lap(hour,minute,second);
}

function resetTimer() {
    stopTimer();
    hour = 0;
    minute = 0;
    second = 0;
    
    document.getElementById('hour').innerText = '00';
    document.getElementById('min').innerText = '00';
    document.getElementById('sec').innerText = '00';
}

function timer() {
    if(isStopped) { // Add this condition
        return;
    }

    second++;
    
    if (second == 60) {
      second = 0;
      minute++;
    }
    if (minute == 60) {
      minute = 0;
      hour++;
    }
    if (hour == 24){
        resetTimer(); 
    }
    document.getElementById('hour').innerText = returnData(hour);
    document.getElementById('min').innerText = returnData(minute);
    document.getElementById('sec').innerText = returnData(second);
}

function returnData(input) {
    return input > 9 ? input : `0${input}`
}

function lap(h,m,s){
    // If all are zero, don't add a lap
    if(h === 0 && m === 0 && s === 0) {
        return;
    }

    const tableLap = document.querySelector("#laps");
    const timerDate = document.createElement("h2");
    const timerNode = document.createTextNode(returnData(h)+":"+ returnData(m)+":"+returnData(s));
    timerDate.appendChild(timerNode);
    tableLap.appendChild(timerDate);
}