function getPageScroll(){

	var yScroll;

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){	 // Explorer 6 Strict
		yScroll = document.documentElement.scrollTop;
	} else if (document.body) {// all other Explorers
		yScroll = document.body.scrollTop;
	}

	arrayPageScroll = new Array('',yScroll) 
	return arrayPageScroll;
}

function getPageSize(){
	
	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	var windowWidth, windowHeight;
	if (self.innerHeight) {	// all except Explorer
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
	
	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight){
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}


	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}

function showpopup(pop)
{
	var objOverlay = document.getElementById('overlay');

	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();

	objOverlay.style.height = (arrayPageSize[1] + 'px');
	objOverlay.style.display = 'block';
	objOverlay.style.zIndex = '999';

	var obj = document.getElementById(pop);
	if(obj)
	{
		obj.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - obj.height) / 2));
		obj.style.left = (((arrayPageSize[0] - obj.width) / 2));
		obj.style.zIndex = '1000';
		obj.style.display = 'block';
	}
	
	// Hide select boxes as they will 'peek' through the image in IE
	selects = document.getElementsByTagName("select");
	for (i = 0; i != selects.length; i++) {
		selects[i].style.visibility = "hidden";
    }
}

//
function hidepopup(pop)
{
	// get objects
	objOverlay = document.getElementById('overlay');
	obj = document.getElementById(pop);

	// hide lightbox and overlay
	objOverlay.style.display = 'none';
	obj.style.display = 'none';

	// make select boxes visible
	selects = document.getElementsByTagName("select");
    for (i = 0; i != selects.length; i++) {
		selects[i].style.visibility = "visible";
	}
}

function initpopup()
{
	if (!document.getElementsByTagName){ return; }
	var objBody = document.getElementsByTagName("body").item(0);
	
	// create overlay div and hardcode some functional styles (aesthetic styles are in CSS file)
	var objOverlay = document.createElement("div");
	objOverlay.setAttribute('id','overlay');
	objOverlay.style.display = 'none';
	objOverlay.style.position = 'absolute';
	objOverlay.style.top = '0';
	objOverlay.style.left = '0';
	objOverlay.style.zIndex = '90';
 	objOverlay.style.width = '100%';
	objBody.insertBefore(objOverlay, objBody.firstChild);
}

function addLoadEvent(func)
{	
	var oldonload = window.onload;
	if (typeof window.onload != 'function'){
    	window.onload = func;
	} else {
		window.onload = function(){
		oldonload();
		func();
		}
	}

}

addLoadEvent(initpopup);	// run initLightbox onLoad