Code:
window.onload = initLinks;

function initLinks() {
	document.getElementById("rotateBack").onclick = rotateBack;
	document.getElementById("rotate").onclick = rotateFor;
}

var thisAd = 0;

var adImages = new Array("catImages/1.png","catImages/2.png","catImages/3.png","shoeImages/4.png","catImages/5.png","catImages/6.png","catImages/7.png","catImages/8.png","catImages/9.png","catImages/10.png");
...