JSFiddle - React, Tailwind, and code Playground

CSS

div.myAjax{
     -webkit-animation:x 700ms ease;
     opacity:1;
    }
    @-webkit-keyframes x{
     0%{opacity:0;}
     100%{opacity:1;}
    }

JavaScript

function fu(){
 var div=document.createElement('div');
 div.className='myAjax';
 div.textContent='ajax stuff';
 document.body.appendChild(div);
}
window.setInterval(fu,3000);