如何使用Chrome扩展功能禁用facebook热键？ [英] How to disable facebook hotkeys with Chrome extension?

问题描述

我已经创建了一个使用热键[Alt] + [0 ... 9]的Chrome扩展程序，只能发现Facebook使用相同的热键。有什么可能的方法我的扩展可以禁用Facebook的热键，以使我的火单独？我确定我已经确定了用于实现他们的[Alt] + [0 ... 9]热键的代码：

  document.documentElement.onkeydown = function（a）{a = a || window.event; var b = a.target || a.srcElement; var c = a.keyCode == 13&！a.altKey& ;&！a.ctrlKey&！a.metaKey&&！a.shiftKey&& CSS.hasClass ... 
  

这是在根文件头部调用的脚本。我尝试过以下操作来禁用它们：

  //内容脚本：
 $（） ）{
 document.documentElement.onkeydown =''; 
}）; 
  

甚至

 code> $（）。ready（function（）{
 document.documentElement.onkeydown = function（e）{}; 
}）; 
  

我进一步猜测，这两个尝试都不能正常工作的原因是因为虽然Chrome扩展内容脚本共享一个DOM与他们运行的任何网页，也许他们不共享编码环境？任何见解将不胜感激！

解决方案

您的直觉是正确的，JavaScript内容脚本作为Chrome扩展程序的一部分运行在一个沙箱中运行，无法访问在包含页面中执行的JavaScript。

根据内容脚本中的Chrome文档：

 但是，内容脚本有一些限制。他们不能：
 *使用chrome。* API（chrome.extension的部分除外）
 *使用由扩展名的页面定义的变量或函数
 *使用由网页定义的变量或函数，由其他内容脚本
  

首先，我建议您考虑不同的快捷键。覆盖您自己的扩展的现有快捷键的功能可以为期待Facebook快捷键的人提供一个刺激的用户体验。想象一下，如果一个扩展覆盖了ctrl-c和ctrl-p快捷方式，这是桌面操作系统的一部分进行复制和粘贴 - 我想你会有一些不高兴的用户，可能会删除改变他们之前学到的行为的东西。 / p>

但是，如果您是坚持的，那么这里是加载将在包含页面的上下文中执行的JavaScript的解决方法：

编辑：更新每个注释以引用插件中的JS文件，而不是在网络上托管的文件

首先，您将需要在您的Chrome插件中创建一个JavaScript文件： override-fb-hotkeys.js 。

，您将需要在Web上的某个地方托管一个JavaScript文件，其中包含您要在页面中执行的脚本，可以说如下： http://mysite.com/override-fb -hotkeys.js 。

然后，从内容脚本中，您可以将脚本标签插入到引用的DOM中您的JavaScript文件，如下所示：

  var script = document.createElement（'script'）; 
 script.setAttribute（type，text / javascript）; 
 script.setAttribute（async，true）; 
 script.setAttribute（src，chrome.extension.getURL（override-fb-hotkeys.js））; //假设你的主机支持http和https 
 var head = document.head || document.getElementsByTagName（head）[0] || document.documentElement中; 
 head.insertBefore（script，head.firstChild）
  

然后将JavaScript抓取，在包含页面的上下文中执行，而不是来自Chrome插件的沙盒代码。

I have created a Chrome extension that uses the hotkeys [Alt]+[0...9] only to discover facebook uses the same hotkeys. Is there any way possible my extension could disable facebook's hotkeys so that mine fire alone? I'm fairly certain I have identified the code facebook uses to implement their [Alt]+[0...9] hotkeys:

document.documentElement.onkeydown=function(a){a=a||window.event;var b=a.target||a.srcElement;var c=a.keyCode==13&&!a.altKey&&!a.ctrlKey&&!a.metaKey&&!a.shiftKey&&CSS.hasClass...

This is in a script called from the head of the root document. I have tried the following to disable them:

//contents script:
$().ready( function() {
  document.documentElement.onkeydown = '';
});

and even

$().ready( function() {
  document.documentElement.onkeydown = function(e){};
});

I am guessing further that the reason neither of these attempts work is because although Chrome extension content scripts share a DOM with any webpage on which they run, perhaps they do not share coding environments? Any insight would be appreciated!

解决方案

You intuition is correct, the JavaScript that runs from a content script as part of a Chrome Extension is run in a sandbox that does not have access to the JavaScript that is executed in the containing page.

Per the Chrome doc on Content Scripts:

However, content scripts have some limitations. They cannot:
*  Use chrome.* APIs (except for parts of chrome.extension)
*  Use variables or functions defined by their extension's pages
*  Use variables or functions defined by web pages or by other content scripts

First off, I would recommend that you consider different shortcut keys. Overriding the functionality of existing shortcut keys for your own extension could provide a jarring user experience for someone that is expecting the Facebook short cut key. Imagine if an extension overrode the ctrl-c and ctrl-p shortcuts that are a part of the desktop OS for copy and paste - I think you would have some upset users that would probably remove the thing that changed the behavior they learned prior.

However, if you are insistent, then here is a workaround to loading JavaScript that will execute in the context of the containing page:

Edit: Updated per comment to reference JS file in plugin instead of one hosted on the web

First, you will need to create a JavaScript file in your chrome plugin: override-fb-hotkeys.js.

First, you will need to host a JavaScript file somewhere on the web that contains the script that you want to execute in the page, lets say you host it at: http://mysite.com/override-fb-hotkeys.js.

Then, from your content script, you can insert a script tag into the DOM that references your JavaScript file, something like this:

    var script = document.createElement('script');
    script.setAttribute("type", "text/javascript");
    script.setAttribute("async", true);
    script.setAttribute("src", chrome.extension.getURL("override-fb-hotkeys.js")); //Assuming your host supports both http and https
    var head = document.head || document.getElementsByTagName( "head" )[0] || document.documentElement;
    head.insertBefore(script, head.firstChild)

The JavaScript will then be fetched and executed in the context of the containing page, not the sandboxed code from the Chrome plugin.

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