For a challenge I was supposed to animate the camera moving but instead resized the box to get the same effect. Works here but if there were other elements things could get screwey.
xxxxxxxxxx
<html>
<head>
<title>Intro to WebGL with three.js</title>
</head>
<body>
<div id="webgl-container"></div>
<script src="//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.js"></script>
<script src="scripts/app.js"></script>
</body>
</html>
https://cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.js