var target_element;
var next_target_element;

var next_image_interval;
var length_of_interval = 12000;
var image_directory;
var images_to_rotate = [];
var current_image_index;

function start_image_slider(new_target_element_id, new_images_to_rotate, new_image_directory, new_length_of_interval)
{
	target_element = document.getElementById(new_target_element_id);
	next_target_element = document.getElementById(new_target_element_id + '-next-image');
	
	if ( ! target_element || ! next_target_element) {
		return;
	}

	clearInterval(next_image_interval);

	images_to_rotate = new_images_to_rotate;

	image_directory = new_image_directory.replace(/([^\/])$/, '$1/');

	if (new_length_of_interval) {
		length_of_interval = new_length_of_interval;
	}

	current_image_index = 0;

	image_slider_activate();
	next_image_interval = setInterval('image_slider_activate()', length_of_interval);
}

function image_slider_activate()
{
	if ( ! images_to_rotate) {
		return;
	}
	target_element.style.backgroundImage = 'url("'
		+ image_directory
		+ images_to_rotate[current_image_index]
		+ '")';
	if (current_image_index == images_to_rotate.length - 1) {
		current_image_index = 0;
	} else {
		current_image_index++;
	}
	next_target_element.src = image_directory + images_to_rotate[current_image_index];
}