JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
<div id="BG01">01</div>
<div id="BG02">02</div> 
<div id="BG03">03</div> 
<div id="BG04">04</div> 
</div>

JavaScript

var b=0;
var a=1;

function setInterval(){
if (b==0) {
    $('#BG0' + a).css({
            "display": "block",
            "z-index": "10",
            "opacity": "1"});
    b=2;
    
}
else {
    if (b===5) {
        b=1;
        $('#BG0' + a).css("z-index", "1");
        $('#BG0' + b).css({
                    "z-index": "10",
                    "display": "block",
                    "opacity": "1"});
        $('#BG0' + a).css({
                    "z-index": "-99",
                    "display": "none",
                    "opacity": "0"});
        a=b;
        b+=1;
        

    }
    else {
        $('#BG0' + a).css("z-index", "1");
        $('#BG0' + b).css({
                    "z-index": "10",
                    "display": "block",
                    "opacity": "1"});
        $('#BG0' + a).css({
                    "z-index": "-99",
                    "display": "none",
                    "opacity": "0"});
        a=b;
        b+=1;          


        }

    }


}
setInterval();