var xinterval = 20; // delay between rotating images (in seconds)
var xrandom_display = 1; // 0 = no, 1 = yes
xinterval *= 1000;

var image_index = 0;
image_list = new Array();

image_list[image_index++] = new imageItem("images/postcard-2.jpg");
image_list[image_index++] = new imageItem("images/postcard-1.jpg");
image_list[image_index++] = new imageItem("images/postcard-3.jpg");
image_list[image_index++] = new imageItem("images/postcard-4.jpg");
image_list[image_index++] = new imageItem("images/postcard-5.jpg");

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

function getNextImage() {
	if (xrandom_display) {
		image_index = generate(0, number_of_image-1);
	} else {
		image_index = (image_index+1) % number_of_image;
	}
	var new_image = get_ImageItemLocation(image_list[image_index]);
	return(new_image);
}

function rotateImage(place) {
	var new_image = getNextImage();
	document.getElementById(place).src = new_image;
	var recur_call = "rotateImage('"+place+"')";
	setTimeout(recur_call, xinterval);
}