Countdown Hours Minutes Seconds

Question

I'd like to create a countdown that count every hours, minutes, seconds remaining to 00:00:00 on July 13th at 12AM Miami time.

I'd like to addapt that code snippet and i struggle with calculs. How shoud i adapt that code snippet for me to display hours, minutes, seconds instead of days, hours, minutes, seconds ?

How should i write the date for it to be 00:00:00 on July 13th at 12AM Miami time ? What should i try next ?

Thanks.

<p id="demo"></p>

<script>
// Set the date we're counting down to
var countDownDate = new Date("Jan 5, 2022 15:37:25").getTime();

// Update the count down every 1 second
var x = setInterval(function() {

  // Get today's date and time
  var now = new Date().getTime();

  // Find the distance between now and the count down date
  var distance = countDownDate - now;

  // Time calculations for days, hours, minutes and seconds
  var days = Math.floor(distance / (1000 * 60 * 60 * 24));
  var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);

  // Display the result in the element with id="demo"
  document.getElementById("demo").innerHTML = days + "d " + hours + "h "
  + minutes + "m " + seconds + "s ";

  // If the count down is finished, write some text
  if (distance < 0) {
    clearInterval(x);
    document.getElementById("demo").innerHTML = "EXPIRED";
  }
}, 1000);
</script>

-- WayneOS code snipped modification

// Format output-string
  var outputHours =  (hours < 10 ? '0' + hours : hours);
  var outputMinutes = (minutes < 10 ? '0' + minutes : minutes);
  var outputSeconds = (seconds < 10 ? '0' + seconds : seconds);

  // Display the result in the element with id="demo"
  if (distance > 0)
      document.getElementById("hours").innerHTML = outputHours;
      document.getElementById("minutes").innerHTML = outputMinutes;
      document.getElementById("seconds").innerHTML = outputSeconds;

  else
      document.getElementById("hours").innerHTML = "EXPIRED";

}, 1000);
```

Answer 1

You could use a loop to calculate the hours, minutes and seconds until distance is smaller than 1000. For it to end on Jul 13 12:00:00 use new Date("Jul 13, 2021 12:00:00 GMT-4") Here is an example.

// Set the date we're counting down to
var countDownDate = new Date("Jul 13, 2021 12:00:00 GMT-4").getTime();

// Update the count down every 1 second
var x = setInterval(function() {

  // Get today's date and time
  var now = new Date().getTime();

  // Find the distance between now and the count down date
  var distance = countDownDate - now;

  // Time calculations for hours, minutes and seconds
  var hours   = 0;
  var minutes = 0;
  var seconds = 0;
  while (true)
    if (distance >= (1000*60*60)) {
    
      hours++;
      distance -= (1000*60*60);
    
    } else
    if (distance >= (1000*60)) {
    
      minutes++;
      distance -= (1000*60);
    
    } else
    if (distance >= 1000) {
    
      seconds++;
      distance -= 1000;
    
    } else
      break;

  // Format output-string
  var hours   = (hours < 10 ? '0' + hours : hours);
      minutes = (minutes < 10 ? '0' + minutes : minutes);
      seconds = (seconds < 10 ? '0' + seconds : seconds);

  // Display the result in the element with id="demo"
  if (distance > 0) {
      document.getElementById("hours").innerHTML = hours;
      document.getElementById("minutes").innerHTML = minutes;
      document.getElementById("seconds").innerHTML = seconds;
  } else
      document.getElementById("hours").innerHTML = "EXPIRED";

}, 1000);

<div id="hours"></div>
<div id="minutes"></div>
<div id="seconds"></div>

Answer 2

If you have days, you can calculate the hours (days * 24 plus remaining hours). Here a little refactoring of your code. It uses setTimeout (more control and counting starts instantly) and a separate function to calculate the time units. See also.

Concerning the Miami time zone, you can create the date using timezone 'America/New_York'.

const getNextJuly13 = () => {
  const now = new Date();
  const miamiTime = new Date(`${
    +(now.getMonth() > 6 && now.getDate() >= 13) + now.getFullYear()}/07/13 00:00`)
    .toLocaleString('en', {timeZone: 'America/New_York'});
  return new Date( miamiTime );
};

countDown(getNextJuly13(), document.querySelector("#demo"));

function countDown(until, writeTo) {
  const distance = until - new Date();
  const diffs = dateDiffCalc(distance);
  const timeInfo4Demo = `\n\n=> Until ${
    until.toLocaleString()} (your TZ: ${
      Intl.DateTimeFormat().resolvedOptions().timeZone})\n${
        JSON.stringify(diffs, null, 2)}`;
  writeTo.textContent = `${diffs.totalHours}h ${
    diffs.minutes}m ${diffs.seconds}s${timeInfo4Demo}`;
  return distance >= 0 
   ? setTimeout(() => countDown(until, writeTo), 1000)
   : writeTo.textContent = "EXPIRED";
};

function dateDiffCalc(milliseconds) {
  const secs = Math.floor(milliseconds / 1000);
  const mins = Math.floor(secs / 60);
  const hours = Math.floor(mins / 60);
  const days = Math.floor(hours / 24);

  return {
    days,
    hours: hours % 24,
    totalHours: (days * 24) + (hours % 24),
    minutes: mins % 60,
    seconds: secs % 60,
  };
}

<pre id="demo"></pre>