setInterval Change Class

set_interval_change_class.js

var slider = document.getElementById("hero");
var classes = ['slide1', 'slide2', 'slide3', 'slide4'];

var myInterval = setInterval(function () {
    changeClass()
}, 5000);

var i = 0;

function changeClass() {
    slider.classList = classes[i];
    i < classes.length - 1 ? i++ : i = 0;
}