var names = new Array("danny", "androo", "ryan", "kawika");
var randI;

function switchAd(node) {
    var showcase = document.getElementById('showcase');
    var img = showcase.getElementsByTagName('img').item(0);
    var adtitle = showcase.getElementsByTagName('h2').item(0);
    img.src = node.id + '.jpg';
    adtitle.innerHTML = node.title;
}

function restoreDefault() {
    var node = document.getElementById(names[randI]);
    switchAd(node);
}

function chooseRandom() {
    randI = Math.round(Math.random() * 3);
    var node = document.getElementById(names[randI]);
    node.parentNode.setAttribute("class", "selected");
    restoreDefault();
}