function emptyElement(target) {
	while (target.hasChildNodes()){
		target.removeChild(target.firstChild);
	}
}


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;
} //end getPageSize

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;
	}

	return yScroll;
} //end getPageScroll

function showLightbox() {
	
	var iframe=document.createElement("iframe");
	iframe.setAttribute("src", "commercials.html");
	iframe.setAttribute("height", "410");
	iframe.setAttribute("width", "530");
	iframe.setAttribute("frameborder", "0");
	document.getElementById("iframe_holder").appendChild(iframe);
	
	var pageSize = getPageSize();
	
	//Hide select boxes as they will 'peek' through the blackout in IE
	var selects = document.getElementsByTagName("select");
	for (i = 0; i < selects.length; i++) {
		selects[i].style.visibility = "hidden";
	} //end i = 0; i < selects.length; i++ FOR
	
	//Blackout screen
	var blackout = document.getElementById("blackout");
	blackout.style.width = (pageSize[0]-10)+"px";
	blackout.style.height = (pageSize[1]-10)+"px";
	blackout.style.display = "block";
	blackout.onclick = hideLightbox;
	
	//Display lightbox
	var target= document.getElementById("lightbox");
	target.style.width = "565px";
	//target.style.height = "150px";
	target.style.left = ((pageSize[2]/2)-282.5)+"px";
	target.style.top = (((pageSize[3]/2)-280)+getPageScroll())+"px";
	target.style.display = "block";
} //end showLightbox

function hideLightbox() {
	//Remove blackout & lightbox
	document.getElementById("blackout").style.display = "none";
	document.getElementById("lightbox").style.display = "none";
	
	//Make select boxes visible
	var selects = document.getElementsByTagName("select");
    for (i = 0; i < selects.length; i++) {
		selects[i].style.visibility = "visible";
	} //end i = 0; i < selects.length; i++ FOR
	
	var target=document.getElementById("iframe_holder");
	emptyElement(target);
} //end hideLightbox