var d = document;

var next;
var prev;

var mainImage;
var slideList = new Array();

var subImage;
var subSlideList = new Array();

var currentSlide = 0;

var text;
var captions;

var func;

function doNext() {
	currentSlide++; 
		
	if( currentSlide >= slideList.length ) {
		currentSlide = 0;
	}
	
	if( func ) {
		func()
	};

	//window.status = (slideList[currentSlide].src + " " + currentSlide);
	mainImage.src = slideList[currentSlide].src;	
}

function doPrev() {
	--currentSlide;
		
	if( currentSlide < 0 ) {
		 currentSlide = slideList.length - 1;
	}
	if( func ) {
		func()
	};

	//window.status = (slideList[currentSlide].src + " " + currentSlide);
	mainImage.src = slideList[currentSlide].src;	
}

//  n - id of "next" button
//  p - id of "prev" button
//  m - id of "main" image (the one that changes)
//  s - list of slide images (needs to be full paths)
//
function installSlideShow( n, p, m, s, f ) {
		
	slides = s;
	
    next = d.getElementById( n );
	prev = d.getElementById( p );
	
	next.onclick = doNext;
	prev.onclick = doPrev;
		
	if( f ) {
		func = f;
	}
		
	mainImage = d.getElementById( m );
		
	for( var i = 0; i < s.length; i++ ) {
		var img = new Image();
		img.src = s[i];
		slideList[ i ] = img;
	}	
}