[NaCl SDK] Simplify graphics3d example.

native_client_sdk/src/examples/api/graphics_3d/example.js

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function $(id) {
+  return document.getElementById(id);
+}
+
+function postAngleMessage() {
+  var xAngle = parseFloat($('xAngle').value);
+  var yAngle = parseFloat($('yAngle').value);
+  common.naclModule.postMessage([xAngle, yAngle]);
+}
+
+// Add event listeners after the NaCl module has loaded.  These listeners will
+// forward messages to the NaCl module via postMessage()
+function attachListeners() {
+  $('xAngle').addEventListener('change', postAngleMessage);
+  $('yAngle').addEventListener('change', postAngleMessage);
+  $('animateOff').addEventListener('click', function() {
+    $('animateOn').checked = '';
+    common.naclModule.postMessage(false);
+  });
+  $('animateOn').addEventListener('click', function() {
+    $('animateOff').checked = '';
+    common.naclModule.postMessage(true);
+  });
+}
+
+// Handle a message coming from the NaCl module.
+function handleMessage(event) {
+  if (!(event.data instanceof Array))
+    return;
+  if (event.data.length != 2)
+    return;
+
+  var xAngle = event.data[0];
+  var yAngle = event.data[1];
+  $('xAngle').value = xAngle;
+  $('yAngle').value = yAngle;
+}