JSFiddle - React, Tailwind, and code Playground

JavaScript

function makeRandomString(len) {
    var res = [];
    for (; len; len--) {
        res.push('qwertyuiopasdfghjklzxcvbnm1234567890-'.charAt(Math.floor(Math.random() * 37)));
    }
    return res.join('');
}

function makeBanner(habra) {
    var bannerUrl;
    var borderColor;
    
    if (habra) {
        bannerUrl = 'http://i.imgur.com/58SRA2N.png';
        borderColor = 'green';
    } else {
        bannerUrl = 'http://perfectapp.perfectinter.net/images/pa_banner_468x60.png';
        borderColor = 'red';
    }
    
    var banner = document.createElement('div');
    banner.setAttribute('id', makeRandomString(16));
    banner.setAttribute('style', [
        "background-image: url('" + bannerUrl + "') !important;",
        "width: 468px !important;",
        "height: 60px !important;",
        "background-repeat: repeat repeat !important;",
        "background-position: center center !important;",
        "cursor: pointer !important;",
        "border: 3px " + borderColor + " solid;"
    ].join(' '));
    
    return banner;
}

var currentBanner = null;

window.setInterval(function() {
    if (currentBanner) {
        document.body.removeChild(currentBanner);
    }
    
    document.body.appendChild(currentBanner = makeBanner(Math.random() < 0.5));
}, 500);