JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div id="result">  
  </div>
</div>
<button onclick="start()">Start</button>

CSS

.container{
  display:flex;
  flex-direction:row;
}

JavaScript

function start() {
  let duration = 2;
  let endTime = new Date();
  endTime.setMinutes(endTime.getMinutes() + duration);
  let min = duration;
  sec = 0;

  let resultDiv = document.getElementById("result");
  let interval = setInterval(() => {

    sec--;
    if (sec == -1) {
      sec = 59;
      min--;
    }

    resultDiv.innerHTML = min.toLocaleString('en-US', {
      minimumIntegerDigits: 2,
      useGrouping: false
    }) + ":" + sec.toLocaleString('en-US', {
      minimumIntegerDigits: 2,
      useGrouping: false
    });

    if ((min == 0) && (sec == 0)) {
      clearInterval(interval);
    }

  }, 1000);

}