var interval = 2.5; // delay between rotating images (in seconds)
var random_display = 0; // 0 = no, 1 = yes
interval *= 1000;

var image_index = 0;
image_list = new Array();
image_list[image_index++] = new imageItem("http://www.pro-physik.de/Phy/logos/LTJ121493959.gif");
//image_list[image_index++] = new imageItem("http://www.pro-physik.de/Phy/logos/NanoS0207_Guide07_310_100.jpg");
image_list[image_index++] = new imageItem("http://www.pro-physik.de/Phy/logos/OP0803_cover_100.jpg");
image_list[image_index++] = new imageItem("http://www.pro-physik.de/Phy/logos/VIP121414055.gif");
image_list[image_index++] = new imageItem("http://www.pro-physik.de/Phy/logos/ISSIMG28185.gif");

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(imagelist) {    

	if (random_display) {
		image_index = generate(0, number_of_image-1);
	}
	else {
		image_index = (image_index+1) % number_of_image;
	}
	var new_image = get_ImageItemLocation(imagelist[image_index]);
	return(new_image);
}

// fuer die Journal Cover 
function rotateImage(place) {
	var new_image = getNextImage(image_list);
	document[place].src = new_image;
	var recur_call = "rotateImage('"+place+"')";
	setTimeout(recur_call, interval);
}