alert（）有时会导致Chrome出错

Question

I used to use alert() for debugging, when I code some lines in JavaScript/jQuery (I know, it is bad style). 我曾经使用alert()进行调试，当我在JavaScript / jQuery中编写一些代码行时（我知道，它是糟糕的样式）。 I now see a strange behaviour in Google Chrome. 我现在在Google Chrome中看到一种奇怪的行为。

HTML HTML

    <html>
    <head>
        <script src="my_script.js"></script>
    </head>
    <body>
    <p>Test</p>
    </body>
    </html>

my_script.js my_script.js

This is really simple. 这很简单。

    alert("hello world");

Error 错误

When I load the page it normally works fine, but when I reload the page sometimes the following error occurs in Google Chrome: 当我加载页面时，它通常可以正常工作，但是当我重新加载页面时，有时 Google Chrome中会出现以下错误：

Uncaught TypeError: Cannot read property 'impl' of undefined extensions::messaging:184 未捕获的TypeError：无法读取未定义扩展的属性'impl':: messaging：184

By testing it several times I found that 通过多次测试，我发现了这一点

the alert() window appears as expected alert()窗口按预期显示
the error occurs not every time but sometimes 错误不是每次都发生，而是偶尔发生
the error occurs (when it occurs) after closing the alert() window 关闭alert()窗口后发生错误（发生时）
the error seems not to occur if I wait to close the alert() window, or between two reloads 如果我等待关闭alert()窗口或两次重新加载之间似乎不会发生错误

The error message points to this code-snippet: 错误消息指向此代码段：

  // In case the extension never invokes the responseCallback, and also
  // doesn't keep a reference to it, we need to clean up the port. Do
  // so by attaching to the garbage collection of the responseCallback
  // using some native hackery.
  messagingNatives.BindToGC(responseCallback, function() {
    if (port) {
      privates(port).impl.destroy_();
      port = null;
    }
  });

But I even couldn't figure out which file is exactly affected and in which folder it is placed. 但我甚至无法确定哪个文件受到了严重影响，以及它放在哪个文件夹中。

Google just found one another description of obviously the same error: https://teamtreehouse.com/forum/anyone-else-getting-error-cannot-read-property-impl-of-undefined 谷歌刚刚发现另一个明显相同错误的描述： https ： //teamtreehouse.com/forum/anyone-else-getting-error-cannot-read-property-impl-of-undefined

The author of this page supposes that the fact, the error occurs only sometimes, points to a problem with an asynchronous process, which is not finished sometimes one reloads the page. 本页的作者假设，事实上，错误只是偶尔发生，指向异步进程的问题，有时候重新加载页面没有完成。

I solved my debugging tasks by switching to the use of console.log() . 我通过切换到console.log()的使用来解决我的调试任务。 But I'm quite interested what error exactly occurs and how I could avoid it to return to my bad style of debugging by using the alert() function. 但是我非常感兴趣的是错误究竟发生了什么以及如何通过使用alert()函数来避免它返回到我糟糕的调试方式。

Answer 1

嘿（：我在这个论坛上找到了你的问题的可能解释（ https://teamtreehouse.com/forum/anyone-else-getting-error-cannot-read-property-impl-of-undefined ）。我引用：'在访问属性impl之前返回undefined。由于它是间歇性发生的，这告诉我，privates（port）是一个异步操作 - 允许其他代码继续执行 - 有时私有将在访问属性impl之前完成，有时它不会。'结束语。即使它只是一种猜测，我发现它是理性的

alert（）有时会导致Chrome出错

问题描述

1 个解决方案

解决方案1
0 2015-08-06 23:11:00

alert（）有时会导致Chrome出错

问题描述

1 个解决方案

解决方案1 0 2015-08-06 23:11:00

解决方案1
0 2015-08-06 23:11:00