/*-----------------------------------------------------------------------------------------------
		
scrollPage.js -- unobtrusive JavaScript functions that control paging. This works faster 
than a roundtrip to server to retrieve more information.
 
Usage:

	(1) Include this file
	(2) Create html tag with an id of "nPages". ie. hidden form value
	(3) Encapsulate the items to be scrolled in a div called "scrollDiv#"
		Where the # = a valid number from 0 to total number of pages defined above
	(4) OPTIONAL - You can specify what next and previous images are used.
		This is done by using additional hidden tags.
		Hidden tag ids should be 'nextImg', 'nextImgRoll', 'prevImg', 'prevImgRoll'
 
Example:
	(1) <script type="text/javascript" src="<%=g_CodePath%>/scrollDiv.js"></script>
	(2) <form name="hiddenvars" id="hiddenvars">
				<input type="hidden" name="nPages" value="<%=divPages%>" id="nPages"></input>
		</form>
	(3)<div id="scrollDiv1" name="scrollDiv1" class="tvDiv" style="">stuff</div>
-----------------------------------------------------------------------------------------------*/

var gCurrentPage = 0;

function getNumPages()
{
	var nPages;
	if (document.getElementById('nPages'))
		nPages = document.getElementById('nPages').value;
	else
		nPages = 3;
	return nPages;
}

function getNextImage()
{
	var nextImg;
	if (document.getElementById('nextImg'))
		nextImg = document.getElementById('nextImg').value;
	else
		nextImg = 'next.gif';
	return nextImg;
}

function getNextImageRoll()
{
	var nextImgRoll;
	if (document.getElementById('nextImgRoll'))
		nextImgRoll = document.getElementById('nextImgRoll').value;
	else
		nextImgRoll = 'nextx.gif';
	return nextImgRoll;
}

function getPrevImage()
{
	var prevImg;
	if (document.getElementById('prevImg'))
		prevImg = document.getElementById('prevImg').value;
	else
		prevImg = 'previous.gif';
	return prevImg;
}

function getPrevImageRoll()
{
	var prevImgRoll;
	if (document.getElementById('prevImgRoll'))
		prevImgRoll = document.getElementById('prevImgRoll').value;
	else
		prevImgRoll = 'previousx.gif';
	return prevImgRoll;	
}

function HideLayers()
{
	var oLayer;

	for(var x = 0; x < getNumPages(); x++)
	{
		oLayer = document.getElementById("scrollDiv" + x);
		oLayer.style.visibility = "hidden";
		oLayer.style.display = "none";
	}
}

function ShowNextLayer()
{
	HideLayers();
	var oLayer;
	gCurrentPage++;
	if(gCurrentPage >= getNumPages())
		gCurrentPage = getNumPages() - 1;

	oLayer = document.getElementById("scrollDiv" + gCurrentPage);
	oLayer.style.visibility = "visible";
	oLayer.style.display = "block";
	
	ShowNavControl();
}

function ShowPrevLayer()
{
	HideLayers();
	
	var oLayer;
	gCurrentPage--;
	
	if(gCurrentPage < 0)
		gCurrentPage = 0;
		
	oLayer = document.getElementById("scrollDiv" + gCurrentPage);
	oLayer.style.visibility = "visible";
	oLayer.style.display = "block";
	
	ShowNavControl();
}

//shows/hides the back & next buttons
function ShowNavControl()
{
	var oBackNext = document.getElementById("backnext");
        //alert(getNumPages());
	
	if (getNumPages() > 1)
	{
		var html = "";
		if (gCurrentPage > 0)
		{
			html += '<a class="navbutton" href="javascript:ShowPrevLayer();">&lt; Previous</a>&nbsp;';
		}
		if (gCurrentPage < (getNumPages() - 1))
		{
			html += '&nbsp;<a class="navbutton" href="javascript:ShowNextLayer();">Next &gt;</a>';
		}
		oBackNext.innerHTML = html;
	}
        //alert(html);
}

//addEvent(window, 'load', ShowNavControl);