JSFiddle - React, Tailwind, and code Playground

HTML

<div class="objects">
                <div class="obj obj-01">01</div>
                <div class="obj obj-02">02</div>
                <div class="obj obj-03">03</div>
                <div class="obj obj-04">04</div>
                <div class="obj obj-05">05</div>
                <div class="obj obj-06">06</div>
                <div class="obj obj-07">07</div>
                <div class="obj obj-08">08</div>
                <div class="obj obj-09">09</div>
                <div class="obj obj-10">10</div>
                <div class="obj obj-11">11</div>
                <div class="obj obj-12">12</div>
                <div class="obj obj-13">13</div>
                <div class="obj obj-14">14</div>
                <div class="obj obj-15">15</div>
            </div>
            
            <div id="countdown"></div>
            
            <div id="objects">0</div>
            
            <form name="count"><input type="hidden" name="time-left"></form>

CSS

.obj { width:30px; height:30px; background:red; margin:10px; }
.objects div { float:left; }

JavaScript

$(document).ready(function(){
    $('.obj').bind('click', function() {
        $(this).unbind('click');
        $(this).fadeOut('slow');
        $("#objects").text( function (i,current) {return +current+1;} );
        return false;
    })
});

function countdown() {
    var seconds = 60;
    function tick() {
        var counter = document.getElementById('countdown');
        seconds--;
        counter.innerHTML = "0:" + (seconds < 10 ? "0" : "") + String(seconds);
        if( seconds > 0 ) {
            setTimeout(tick, 1000);
        } else {
            alert("Game over");
        }
    }
    tick();
}
// start the countdown
countdown();