function getElementsByClassName(classname) {
	node = document.getElementsByTagName("body")[0];
	var a = [];
	var re = new RegExp('\\b' + classname + '\\b');
	var els = node.getElementsByTagName("*");
	for(var i = 0, j = els.length; i < j; i++) {	
		if (re.test(els[i].className)) {
			a.push(els[i]);
		}
	}
	return a;
}

function showElement(element) {
	element.style.display = "block";
}

function hideElement(element) {
	element.style.display = "none";
}

function hideOverlay() {
	document.getElementById("overlay").style.display = "none";
	document.getElementById("overlayContent").innerHTML = "";
}

function showOverlay() {
	document.getElementById("overlay").style.display = "block";
}