expDate = new Date;
expDate.setTime(expDate.getTime()+365*24*60*60*1000);

var imgSet = new Array()
imgSet[0] = "rotate-ad-1.jpg"
imgSet[1] = "rotate-ad-2.jpg"
imgSet[2] = "rotate-ad-3.jpg"
imgSet[3] = "rotate-ad-4.jpg"
imgSet[4] = "rotate-ad-5.jpg"

function setCookie(isName,isValue,dExpires){

document.cookie = isName+"="+isValue+";expires="+dExpires.toGMTString();
}

function selectImage(){

prevImage = document.cookie.substring(8,document.cookie.length)
if (!prevImage || prevImage == imgSet.length-1){currImage = 0}
else {
prevImage++;
currImage = prevImage;
}
setCookie('nVisits',currImage,expDate);
document.getElementById('stepImg').src = imgSet[currImage];

}

window.onload=selectImage;