var thImgWdth	= "59";						//the width of individual thumbnail image
var thImgHght	= "38";						//the height of individual thumbnail image
var thNum	= 4;								//number of thumbnail images to display
var scrSpd	= 2;								//speed in which to scroll thumbnail images
var sldrPos	= "relative";						//position style of thumbnail DIV
var sldrTop	= "0";							//top position of thumbnail DIV
var sldrLft = "0";								//left position of thumbnail DIV

isNS4 = (document.layers) ? true : false;
isIE4 = (document.all && !document.getElementById) ? true : false;
isIE5 = (document.all && document.getElementById) ? true : false;
isNS6 = (!document.all && document.getElementById) ? true : false;

var intOn = "";
var endPos;
var sldrWdth = thImgWdth * thNum;

function createLayer () {
	var thFrm = (document.getElementById) ?
			document.getElementById('thFrame') : ((document.all) ?
					document.all.thFrame : document.layers['thFrame']);
	var sldrStyleTxt = 'position:' + sldrPos + ';';
	sldrStyleTxt += 'top:' + sldrTop + ';';
	sldrStyleTxt += 'left:' + sldrLft + ';';
	sldrStyleTxt += 'width:' + sldrWdth + ';';
	sldrStyleTxt += 'height:' + thImgHght + ';';
	sldrStyleTxt += 'overflow:visible;white-space:nowrap;';
	var cloneImg = document.createElement('img');
	var sldr = document.createElement('div');
	
	sldr.setAttribute('id', 'slider');
	if (isNS6) {sldr.setAttribute('style', sldrStyleTxt);}
	if (isIE5) {sldr.style.cssText = sldrStyleTxt;}
	cloneImg.setAttribute('border', '0');
	cloneImg.setAttribute('width', thImgWdth);
	cloneImg.setAttribute('height', thImgHght);

	for (i = 0; i < thumbImages[selectedIndex].length; i++) {
		var cldImg = cloneImg.cloneNode(false);
		cldImg.setAttribute('id', i);
		cldImg.src = thumbImages[selectedIndex][i];
		cldImg.onclick = showPic;
		cldImg.onmouseover = chgCursor;
		sldr.appendChild(cldImg);
		}
	thFrm.appendChild(sldr);
	
	document.getElementById('picture').src = largeImages[selectedIndex][0];
	document.getElementById('picDesc').innerHTML = descriptions[selectedIndex][0] + "&nbsp;";
	}

function changeGallery(obj){
	selectedIndex = obj.selectedIndex;
	var thFrm = document.getElementById('thFrame');	
	thFrm.innerHTML="";
	
	createLayer();
	}

function showPic (evt) {
	intOn	= true;
	evt = (evt) ? evt : ((window.event) ? window.event : false);
	if (evt) {
		var elem = (evt.target) ? evt.target : evt.srcElement;
		if (elem) {
			var index = parseInt(elem.getAttribute("id"));
			document.getElementById('picture').src = largeImages[selectedIndex][index];
			document.getElementById('picDesc').innerHTML = descriptions[selectedIndex][index] + "&nbsp;";
		}
	}
	intOn	= false;
}

function chgCursor (evt) {
	evt = (evt) ? evt : ((window.event) ? window.event : flase);
	if (evt) {
		var elem = (evt.target) ? evt.target : evt.srcElement;
		if (elem) {
			if (evt.type == "mouseover") { elem.style.cursor = "pointer"; }
			else if (evt.type == "mouseout") { elem.style.cursor = "default"; }
			}
		}
	}

function scrollRgt () {
	var curPos = getSldrPos();
	if ( curPos >= endPos ) {
		clearInterval(intOn);
		intOn = "";return;
		}
	curPos += scrSpd;
	assignSldrPos(curPos);
	}

function scrollLft () {
	var curPos = getSldrPos();
	if ( curPos <= endPos ) {
		clearInterval(intOn);
		intOn = "";return;
		}
	curPos -= scrSpd;
	assignSldrPos(curPos);
	}
function getSldrPos () {
	var Pos;
	if (isNS6) {Pos = parseInt(document.getElementById('slider').style.left);}
	else if (isIE5) {Pos = document.getElementById('slider').style.posLeft;}
	return Pos;
	}
function assignSldrPos (Pos) {
	if (isNS6) {document.getElementById('slider').style.left = Pos + "px";}
	else if (isIE5) {document.getElementById('slider').style.posLeft = Pos;}
	}

function slideIt (way) {
	if ( intOn ) { return; }
	var veryEnd = -1*(thumbImages[selectedIndex].length*thImgWdth);
	var pos	= getSldrPos();
	if ( way == "left" ) {
		var nextPos = pos - sldrWdth;
		var nextEnd	= nextPos - sldrWdth;
		if ( nextEnd > veryEnd ) {endPos = nextPos;}
		else {endPos = pos - (sldrWdth - (veryEnd - nextEnd));}
		intOn	= setInterval( "scrollLft()", 1 );
		}
	if ( way == "right" ) {
		var nextPos = pos + sldrWdth;
		if ( nextPos < 0 ) {endPos = nextPos;}
		else {endPos = pos + (sldrWdth - nextPos);}
		intOn = setInterval( "scrollRgt()", 1 );
		}
	}