var interval = 2200;
var random_display = 0;
var imageDir = "images_sequence/";

var imageNum = 0;
imageArray = new Array();
imageArray[imageNum++] = new imageItem(imageDir + "pic01.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic02.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic03.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic04.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic05.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic06.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic07.gif");
imageArray[imageNum++] = new imageItem(imageDir + "pic08.gif");


var totalImages = 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, totalImages-1);
}
else {
imageNum = (imageNum+1) % totalImages;
}

var new_image = get_ImageItemLocation(imageArray[imageNum]);
return(new_image);
}

function getPrevImage() {
imageNum = (imageNum-1) % totalImages;
var new_image = get_ImageItemLocation(imageArray[imageNum]);
return(new_image);
} 

function prevImage(place) {
var new_image = getPrevImage();
document[place].src = new_image;
}

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

}