function showLoadingScreen(){
	
	loadingScreen_set_interface();
	
}
function loadingScreen_set_interface() {
		
	$('body').append('<div id="jquery-overlay"></div>  <div id="jquery-lightbox"><div id="lightbox-container-loading-box"><div id="lightbox-container-image"><h3>Een moment geduld a.u.b.</h3><img src="fileadmin/na/templates/images/loaders/loader.gif" width="100" height="100" alt="Bezig met laden..."/></div></div></div>');			
	// Get page sizes
	var arrPageSizes = ___getPageSize();
	// Style overlay and show it
	$('#jquery-overlay').css({
		backgroundColor:	'#000000',
		opacity:			0.8,
		width:				arrPageSizes[0],
		height:				arrPageSizes[1]
	}).fadeIn();
	// Get page scroll
	var arrPageScroll = ___getPageScroll();
	// Calculate top and left offset for the jquery-lightbox div object and show it
	$('#jquery-lightbox').css({
		top:	arrPageScroll[1] + (arrPageSizes[3] / 10),
		left:	arrPageScroll[0]
	}).show();
	
	// If window was resized, calculate the new overlay dimensions
	$(window).resize(function() {
		// Get page sizes
		var arrPageSizes = ___getPageSize();
		// Style overlay and show it
		$('#jquery-overlay').css({
			width:		arrPageSizes[0],
			height:		arrPageSizes[1]
		});
		// Get page scroll
		var arrPageScroll = ___getPageScroll();
		// Calculate top and left offset for the jquery-lightbox div object and show it
		$('#jquery-lightbox').css({
			top:	arrPageScroll[1] + (arrPageSizes[3] / 10),
			left:	arrPageScroll[0]
		});
	});
}

function hideLoadingScreen() {
	
	$('#jquery-lightbox').remove();
	$('#jquery-overlay').fadeOut(function() { $('#jquery-overlay').remove(); });
	
}

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;
};

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;
};