var overlayDurationTaf = 0.3;

function initTaf() {
	var objBody = document.getElementsByTagName("body").item(0);
		
	var objOverlay = document.createElement("div");
	objOverlay.setAttribute('id','tafOverlay');
	objOverlay.style.display = 'none';
	objOverlay.onclick = function() { closeTAF(); }
	objBody.appendChild(objOverlay);
}

function openTAF(){
	$$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'hidden' });
	
	var arrayPageSize = getPageSize();
	$('tafOverlay').setStyle({ width: arrayPageSize[0]+'px' });
	$('tafOverlay').setStyle({ height: arrayPageSize[1]+'px' });
	$('tafOverlay').appear({ duration: overlayDurationTaf, from: 0.0, to: 0.5 });
	
	new Effect.Opacity('taf', {duration:0.0, from:0.0, to:0.0});
	$('taf').style.display = "block";
	
	var tafHeight = $('taf').offsetHeight;
	var tafWidth = $('taf').offsetWidth;
	
	$('taf').style.display = "none";
	
	var arrayPageScroll = getPageScroll();
	var lightboxTop = arrayPageScroll[1] + (arrayPageSize[1] / 2) - (tafHeight);
	var lightboxLeft = arrayPageScroll[0] + (arrayPageSize[0] / 2) - (tafWidth / 2);
	$('taf').setStyle({ top: lightboxTop+'px' });
	$('taf').setStyle({ left: lightboxLeft+'px' });
	
	new Effect.Appear('taf', {duration:overlayDurationTaf, from:0.0, to:1});
}

function closeTAF(){
	new Effect.Fade('tafOverlay', { duration: overlayDurationTaf});
	$$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'visible' });
	new Effect.Fade('taf', { duration: overlayDurationTaf});
}

function toggleTAF(){
	if(document.getElementById('taf').style.display == "none"){
		openTAF();	
	}else{
		closeTAF();
	}
}

function getPageSize() {
	        
	     var xScroll, yScroll;
		
		if (window.innerHeight && window.scrollMaxY) {	
			xScroll = window.innerWidth + window.scrollMaxX;
			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
			if(document.documentElement.clientWidth){
				windowWidth = document.documentElement.clientWidth; 
			} else {
				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 = xScroll;		
		} else {
			pageWidth = windowWidth;
		}

		return [pageWidth,pageHeight];
	}
	
	function getPageScroll(){

	var xScroll, yScroll;

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

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

Event.observe(window, 'load', initTaf, false);