Someone

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<style>
			html, body {
		    	margin: 0;
			    padding: 0;
			    width: 100%;
			    height: 100%;
			}

			#pageBlanket {
				background-color: blue;
				border: thick dotted black;
				width: 100%;
				height: 100%;
				color: white;
				z-index: 499;
			}
		</style>

		<title></title>
	</head>
	<body>
		<div
			style="margin: auto; background-color: rgb(204, 204, 204); width: 403px; position: relative;">
			<p>
				This is opaque div. This is opaque div. This is opaque div. This is
				opaque div. This is opaque div. This is opaque div. This is opaque
				div.
			</p>
			<p>
				This is opaque div. This is opaque div. This is opaque div. This is
				opaque div. This is opaque div. This is opaque div. This is opaque
				div.
			</p>
			<p>
				This is opaque div. This is opaque div. This is opaque div. This is
				opaque div. This is opaque div. This is opaque div. This is opaque
				div.
			</p>
		</div>
		<input type="button" />
		<script>
			alert("it's going to happen!");
			var blanket = document.createElement("div");
			blanket.id = "pageBlanket";
			blanket.innerHTML = "Blah!";
			document.body.appendChild(blanket);
		</script>
	</body>
</html>