JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mainpanel">  
    <div>  
        test  
    </div>  
    <div class="shortly">  
        shortly
    </div>  
    <button class="resetButton">  
        Reset  
    </button>

CSS

.mycount
{
    background-color:green;
}

JavaScript

(function($) { 
    function countdown(el, options) { 
        var calc = function (target, current) { 
            /* Return true if the target date has arrived, 
            * an object of the time left otherwise. 
            */ 
            var current = current || new Date(); 
            if (current >= target) { return true; } 
            
            var o = {}; 
            var remain = Math.floor((target.getTime() - current.getTime()) / 1000); 
            
            o.days = Math.floor(remain / 86400); 
            remain %= 86400; 
            o.hours = Math.floor(remain / 3600); 
            remain %= 3600; 
            o.minutes = Math.floor(remain / 60); 
            remain %= 60; 
            o.seconds = remain; 
            o.years = Math.floor(o.days / 365); 
            o.months = Math.floor(o.days / 30); 
            o.weeks = Math.floor(o.days / 7); 
            
            return o; 
        }; 
        
        var getWeek = function(date) {  
            var onejan = new Date(date.getFullYear(),0,1); 
            return Math.ceil((((date - onejan) / 86400000) + onejan.getDay())/7); 
        }; 
        
        var options = $.extend({ 
            date: new Date(), 
            modifiers: [], 
            interval: 1000, 
            msgFormat: '%d [day|days] %hh %mm %ss', 
            msgNow: 'Now !' 
        }, options); 
        
        var tokens = { 
            y: new RegExp ('\\%y(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // years  
            M: new RegExp ('\\%M(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // months  
            w: new RegExp ('\\%w(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // weeks 
            d: new RegExp ('\\%d(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // days 
            h: new RegExp ('\\%h(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // hours 
            m: new RegExp ('\\%m(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g'), // minutes 
            s: new RegExp ('\\%s(.+?)\\[(\\w+)\\|(\\w+)\\]', 'g')  // seconds 
        }; 
        
        var formatToken...