JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1"></div>
<div id="div2"></div>

CSS

#div1 {
    height:100px;
    width:100px;
    background-color:red;
    position:absolute;
}
#div2 {
    height:100px;
    width:100px;
    background-color:blue;
    display:none;
    position: absolute;
}

JavaScript

for (var i = 0; i < 10; i++) {
    setTimeout(function () {
        $('#div1').fadeToggle(600);
        $('#div2').fadeToggle(600);
    }, 1000);
}