function hideOverlayer(){
	var obg = document.getElementById('page-bg');
	var ovr = document.getElementById('overlayer');

	ovr.style.display = 'none';
	obg.style.display = 'none';

}

function showOverlayer(title,url){
	
	loading = 'images/loading.gif';
	document.getElementById("img_preview").src = '';
	document.getElementById("img_preview").src = loading;
	document.getElementById("img_preview").src = url;
	document.getElementById("overlayer_title").innerHTML = title;
	
	var size = getPageSize();
	var scroll = getPageScroll();

	var obg = document.getElementById('page-bg');
	obg.style.width = size[0]+'px';
	obg.style.height = size[1]+'px';
	
	var ovr = document.getElementById('overlayer');
	
	obg.style.display = 'block';
	ovr.style.display = 'block';

	sizes = getPageSize();
	left = parseInt((sizes[0] - 475) / 2) ;
	ovr.style.left = left + 'px'; 
	
}

function getPageScroll(){
     var scrolly = typeof window.pageYOffset != 'undefined' ? window.pageYOffset : document.documentElement.scrollTop;   
     var scrollx = typeof window.pageXOffset != 'undefined' ? window.pageXOffset : document.documentElement.scrollLeft;   
	
	var arrayScroll = new Array(scrollx, scrolly);
	return arrayScroll;	
}

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;
}