Chrome Native Client，使用 onKeyDown 事件时出错

发布于 2025-01-04 12:19:43 字数 1180 浏览 2 评论 0原文

我正在尝试运行一个非常基本的 Chrome Native Client 应用程序。我想做的是响应击键，例如每当用户按下某个键时显示“您按下了 X”。我已经花了一整天的时间，但每次按下一个键，我都会收到“Uncaught TypeError: Object # has no method 'postMessage'”。

错误全部在 Javascript 中； Native Client C++ 模块工作正常。

文档头部中的Javascript：

myModule = null;  // Global application object.

function moduleDidLoad() {
    myModule = document.getElementById('mymodule');

    alert("module loaded!") // this works

    myModule.postMessage('hello'); // this works, and posts 'hello' to the module

   // ERROR
   document.body.onkeydown = function() {myModule.postMessage('hi');}
}

在页面中：

<div id="listener">
   <script type="text/javascript">

     var listener = document.getElementById('listener');
      listener.addEventListener('load', moduleDidLoad, true);

   </script>

  <embed name="nacl_module"
   id="mymodule"
   width=0 height=0     
   src="mymodule.nmf"
   type="application/x-nacl" />
</div>

我尝试了大约15种不同的方法：通过使用addEventListener将其添加到body标签，通过使用onKeyDown将其直接添加到body标签......没有任何效果。

我有 C/C++ 和 PHP 经验，但我的 Javascript 确实很弱。我想我一定错过了一些基本且明显的东西。

原文

I'm trying to get a very basic Chrome Native Client application running. What I'd like to do is respond to keystrokes, for example by displaying "You pressed X" whenever a user presses a key. I've been at it all day, but every time I press a key, I get "Uncaught TypeError: Object # has no method 'postMessage'".

The errors are all in the Javascript; the Native Client C++ module works fine.

Javascript in head of document:

myModule = null;  // Global application object.

function moduleDidLoad() {
    myModule = document.getElementById('mymodule');

    alert("module loaded!") // this works

    myModule.postMessage('hello'); // this works, and posts 'hello' to the module

   // ERROR
   document.body.onkeydown = function() {myModule.postMessage('hi');}
}

In page:

<div id="listener">
   <script type="text/javascript">

     var listener = document.getElementById('listener');
      listener.addEventListener('load', moduleDidLoad, true);

   </script>

  <embed name="nacl_module"
   id="mymodule"
   width=0 height=0     
   src="mymodule.nmf"
   type="application/x-nacl" />
</div>

I've tried it about 15 different ways: by adding it to the body tag with addEventListener, by adding it directly to the body tag with onKeyDown... nothing works.

I have experience with C/C++ and PHP but my Javascript is really weak. I think I must be missing something fundamental and obvious.

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