Object.extend(Element, {
	getWidth: function(element) {
	   	element = $(element);
	   	return element.offsetWidth; 
	},
	setWidth: function(element,w) {
	   	element = $(element);
    	element.style.width = w +"px";
	},
	setHeight: function(element,h) {
   		element = $(element);
    	element.style.height = h +"px";
	},
	setTop: function(element,t) {
	   	element = $(element);
    	element.style.top = t +"px";
	},
	setLeft: function(element,l) {
	   	element = $(element);
    	element.style.left = l +"px";
	},
	setSrc: function(element,src) {
    	element = $(element);
    	element.src = src; 
	},
	setHref: function(element,href) {
    	element = $(element);
    	element.href = href; 
	},
	setInnerHTML: function(element,content) {
		element = $(element);
		element.innerHTML = content;
	}
});

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;
	}

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



	Overlay = Class.create ({
	   initialize : function() {
			if (!this.objOverlay) { 	
	   			var objBody = document.getElementsByTagName("body")[0];
				this.objOverlay = document.createElement("div");

				if (document.all) {
					this.objIframe = document.createElement("iframe");
					this.objOverlay.appendChild(this.objIframe);
				}
				
				this.objOverlay.setAttribute('id','overlay');
				this.objOverlay.style.display = 'none';
				objBody.insertBefore(this.objOverlay, objBody.firstChild);
	   		}		
		 },
		 show: function() {
			var arrayPageSize = getPageSize();
			
			Element.setHeight(this.objOverlay, arrayPageSize[1]);

			if (this.objIframe) {
				Element.setWidth(this.objIframe, arrayPageSize[0]);
				Element.setHeight(this.objIframe, arrayPageSize[1]);
			}
			
			new Effect.Appear(this.objOverlay, { duration: 0.2, from: 0.0, to: 0.8 });				
		 },
		 hide: function() {
			new Effect.Fade(this.objOverlay, { duration: 0.2});	
		 }
	});

	
	Overlay.getInstance = function() {
		if (!Overlay._instance) {
			Overlay._instance = new Overlay();
		}	
		return Overlay._instance;
	}

	var overlay = null;