JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    Hello World
</div>

JavaScript

(function() {
    setInterval(function(){
        $("#container").append('<div class="item new">New Item</div>');
    }, 3000);
    
    setInterval(function() {
        $('.item').css('color', 'red');
        $('.item').removeClass('new');
    }, 100);
})();