[NaCl SDK] Messaging example (demonstrates postMessageAndAwaitResponse)

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

+// Copyright (c) 2014 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.querySelector(id);
+}

[dmichael (off chromium), 2014/12/03 23:33:33]

I wouldn't define $ in an example...  you can just call querySelector directly.

If somebody blindly copy-pastes, they'll break other libraries that define it
(obvious example being jQuery).

[binji, 2014/12/03 23:56:50]

Done.

+
+function attachListeners() {
+  var number1El = $('#addend1');
+  var number2El = $('#addend2');
+  var resultEl = $('#result');
+
+  document.getElementById('addAsync').addEventListener('click', function() {
+    var value1 = parseInt(number1El.value);
+    var value2 = parseInt(number2El.value);
+    common.naclModule.postMessage([value1, value2]);
+
+    // The result is returned in handleMessage below.
+  });
+
+  document.getElementById('addSync').addEventListener('click', function() {
+    var value1 = parseInt(number1El.value);
+    var value2 = parseInt(number2El.value);
+    var result =
+        common.naclModule.postMessageAndAwaitResponse([value1, value2]);
+
+    // This is the result returned from the module synchronously (i.e. when the
+    // addSync button is pressed)
+    resultEl.textContent = result;
+  });
+}
+
+// Called by the common.js module.
+function handleMessage(message_event) {
+  // This is the result returned from the module asynchronously (i.e. when the
+  // addAsync button is pressed)
+  result.textContent = message_event.data;
+}