The main use of the setInterval () method:
<img id='img' src='img/轮播01.png'>
<script>
let img = document.querySlector('img');
// initialize the timer
let timer = null;
let n = 0;
timer = setInterval(()=>{
n++
// If n is greater than the rotation cycle to the number of pictures, then re-start from the first picture carousel
if (n> the number of image rotation) {
n = 1;
}else{
img.src = "img/轮播0" + n + ".png";
},1000)