jQuery Countdown using a single timezone and 24 hour reset

I recently worked on a project where the client wanted a constantly running 24 hour countdown. The countdown needed to reset automatically at 3pm and needed to be synced up with Eastern Standard Time (EST). I turned to the jQuery countdown plugin by Keith Wood.

This snippet will work out of the box with a few tweaks based on your current needs.

Update the path to servertime.php (don’t forget to create this file and add the contents below)
Update both times (current day and next day – lines 31 & 35)
Update the class or id being targeted on line 48

That’s it!

	jQuery(document).ready(function($) {

	/* servertime.php

	<?php
	$now = new DateTime();
	echo $now->format("M j, Y H:i:s O")."\n";
	?>

	*/

	jQuery(document).ready(function($) {

	function serverTime() {
	var time = null;
	$.ajax({url: 'path-to/servertime.php',
	async: false, dataType: 'text',
	success: function(text) {
	time = new Date();
	},
	error: function(http, message, exc) {
	time = new Date();
	}});
	return time;

	}

	function getCountDown() {
	var until = getNowEDT();

	until.setHours(15,0,0,0); // 3PM current day

	if(getNowEDT() >= until){
	until.setHours(39,0,0,0); // 3PM next day
	}



	return until;
	}

	function getNowEDT() {
	var now = new Date();
	now.setMinutes(now.getMinutes() + now.getTimezoneOffset() - 4 * 60); // EDT is UTC-4
	return now;
	}

	$('#home-timer').countdown({until: getCountDown(), compact: true, serverSync: serverTime, format: 'HMS', timezone: -4,
	onExpiry: function() {
	$(this).countdown('option', {until: getCountDown()});
	}});
	});

	// Another quick example of how to handle 24 hour countdown reset (without the timezone sync)
	function doCountdown(){

	var todaysThree = new Date(), nextThree = new Date();
	todaysThree.setHours(15,0,0,0);
	if (todaysThree <= nextThree){ nextThree.setDate(nextThree.getDate()+1); }
	nextThree.setHours(15,0,0,0);

	$('#home-timer').countdown({until: nextThree, compact: true,
	description: '', onExpiry: function(){doCountdown()}});
	}
	doCountdown();

	// http://keith-wood.name/countdownRef.html
	// https://forum.jquery.com/topic/countdown-plugin-how-to-restart-countdown-timer-every-24-hours

	});