threejs sandbox

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/three.js/r68/three.min.js"></script>
<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - gltf exporter</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<style>
			body {
				font-family: Monospace;
				background-color: #000;
				margin: 0px;
				overflow: hidden;
			}
			#info {
				color: #ccc;
				text-align: center;
				position: absolute;
				top: 0px; width: 100%;
				padding: 5px;
			}
		</style>
	</head>
	<body>
		<div id="info">
			GLTF Exporter<br/>
			<button id="export_scene">Export Scene1</button>
			<button id="export_scenes">Export Scene1 and Scene 2</button>
			<button id="export_object">Export Sphere</button>
			<button id="export_obj">Export WaltHead</button>
			<button id="export_objects">Export Sphere and Grid</button>
			<button id="export_scene_object">Export Scene1 and Sphere</button>
			<br/>
			<label><input id="option_trs" name="trs" type="checkbox"/>TRS</label>
			<label><input id="option_visible" name="visible" type="checkbox" checked="checked"/>Only Visible</label>
			<label><input id="option_drawrange" name="visible" type="checkbox" checked="checked"/>Truncate drawRange</label>
			<label><input id="option_binary" name="visible" type="checkbox">Binary (<code>.glb</code>)</label>
			<label><input id="option_forceindices" name="visible" type="checkbox">Force indices</label>
			<label><input id="option_forcepot" name="visible" type="checkbox">Force POT textures</label>
		</div>

		<script src="../build/three.js"></script>

		<script src="js/Detector.js"></script>
		<script src="js/loaders/OBJLoader.js"></script>
		<script src="js/exporters/GLTFExporter.js"></script>

		<script>
			function exportGLTF( input ) {
				var gltfExporter = new THREE.GLTFExporter();
				var options = {
					trs: document.getElementById('option_trs').checked,
					onlyVisible:...