w3 school timer

by ShaCP

CSS

body {
  font-size: 8rem;
}

JavaScript

var startTime = Math.floor(Date.now() / 1000); //Get the starting time (right now) in seconds
localStorage.setItem("startTime", startTime); // Store it if I want to restart the timer on the next page

function startTimeCounter() {
debugger;
    var now = Math.floor(Date.now() / 1000); // get the time now
    var diff = now - startTime; // diff in seconds between now and start
    var m = Math.floor(diff / 60); // get minutes value (quotient of diff)
    var s = Math.floor(diff % 60); // get seconds value (remainder of diff)
    m = checkTime(m); // add a leading zero if it's single digit
    s = checkTime(s); // add a leading zero if it's single digit
    document.body.innerHTML = m + ":" + s; // update the element where the timer will appear
    var t = setTimeout(startTimeCounter, 500); // set a timeout to update the timer
}

function checkTime(i) {
    if (i < 10) {i = "0" + i};  // add zero in front of numbers < 10
    return i;
}

startTimeCounter();