var interval = 240000; // 240000 milliseconds = 240 seconds. 
var random_display = 0;
var image_dir = "images/homepage/2008Aug/AdBanner_"
var ImageNum = 0;

imageArray = new Array();
// To add new banners.
// Step 1.) Create banner images called "banner_xx.jpg" (where x is a number) and put in the images folder
// Step 2.) Add new rows below while only changing the banner's image number.
imageArray[ImageNum++] = new imageItem(image_dir + "1.jpg");
imageArray[ImageNum++] = new imageItem(image_dir + "2.jpg");


var number_of_image = imageArray.length;

function imageItem(image_location) {
	this.image_item = new Image();
	this.image_item.src = image_location;
}

function get_ImageItemLocation(imageObj) {
	return(imageObj.image_item.src)
}

function randNum(x, y) {
	var range = y - x + 1;
	return Math.floor(Math.random() * range) + x;
}

function getNextImage() {
	if (random_display) {
		ImageNum = randNum(0, number_of_image-1);
	}
	else {
		ImageNum = (ImageNum+1) % number_of_image;
	}
	var new_image = get_ImageItemLocation(imageArray[ImageNum]);
	return(new_image);
}

function rotateImage(place) {
  if (document[place]) {
	var new_image = getNextImage();
	document[place].src = new_image;
	var recur_call = "rotateImage('"+place+"')";
	timerID = setTimeout(recur_call, interval);
  }
}