function show(elementID) {
	div = document.getElementById(elementID);				
	div.style.display = "block";
	div.style.visibility = "";	  
}

function hide(elementID) {
	div = document.getElementById(elementID);				
	div.style.display = "none";
	div.style.visibility = "hidden";
}

function centerHelpBox(elementID) {
	var helpBox = document.getElementById(elementID);
	if (window.innerWidth) {
		var offsetX = (window.innerWidth - 400) / 2;
		var offsetY = (window.innerHeight - helpBox.offsetHeight) / 2;
	} else {
		var offsetX = (screen.availWidth - 400) / 2;
		var offsetY = (screen.availHeight - helpBox.offsetHeight) / 2;
	}
	helpBox.style.left = offsetX + "px";
	helpBox.style.top = offsetY + "px";
}