JSFiddle - React, Tailwind, and code Playground

HTML

<div class="relative">
	<div id="div1" class="div1  div1-color top" ></div>
	<div id="div2" class="div2  div2-color " ></div>
</div>

CSS

.relative {
    position: relative;
    z-index: 2;
}

.div1, .div2 {
    width: 500px;
    height: 500px;
    position: absolute;
}

.top {
    z-index: 5;
}

.div1-color {
    background: black;
}

.div2-color {
    background: red;
}

JavaScript

var currentDiv = "div2";

setInterval(function() {

    console.log(currentDiv);
    
    if (currentDiv == "div2") {
     	$('#'+currentDiv).addClass("top");
        $('#div1').removeClass("top");
        currentDiv = "div1";
    } else {
        $('#'+currentDiv).addClass("top");
        $('#div2').removeClass("top");
        currentDiv = "div2";
    }
    
}, 5000);