var interval = 4000; //In JavaScript, 1000 is equal to one second, so I've set mine at 1.5 seconds. 
var random_display = 0; //In this case, 0 is equal to sequential, 1 is equal to random.
var imageDir = "images/";
// var captionText = "";
var imageNum = 0;
var captionNum = 0;
var totalImages = 0;

imageArray = new Array();
captionArray = new Array();

function initImgs (arrOfImgNames) {
//alert("hello");
numImgs = arrOfImgNames.length;

//alert(arrOfImgNames.length)

	for(i = 0; i <= numImgs -1 ; i++)
	{
//	alert(arrOfImgNames[i])
       imageArray[i] = new imageItem(imageDir + arrOfImgNames[i]);
//       captionArray[i] = "";
	}
	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)
}

//Since we might want to display our images randomly. we need a function to generate 
//some random index numbers for us. 

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]);
// captionText = captionArray[imageNum];
//alert(captionArray[imageNum]);
//alert(captionText);
return(new_image);
}

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

function prevImage(place) {
var new_image = getPrevImage();
document[place].src = new_image;
// document.getElementById('captionarea').innerHTML = captionText;
}

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