可以通过Chrome扩展程序修改窗口对象吗？ [英] Can the window object be modified from a Chrome extension?

问题描述

我想制作一个Chrome扩展程序，它在窗口中提供了一个新对象。当浏览器中加载了扩展的浏览器中查看网页时，我想通过Javascript提供 window.mything 。 window.mything 对象将具有一些我将在扩展中定义的函数，这些函数应该可以从 console.log 或任何Javascript文件，当页面在启用了扩展名的浏览器中查看时。

我可以通过使用 Content Script ：

  var s = document.createElement（script）; 
 s.src = chrome.extension.getURL（mything.js）; 
 document.getElementsByTagName（head）[0] .appendChild（s）; 
  

mything.js看起来像这样：

  window.mything = {thing：true}; 
 console.log（window）; 
  

每当页面加载时，我会看到整个窗口对象，因为我期望它在控制台中。但是，我无法与控制台中的 window.mything 对象进行交互。看来如果注入的脚本还没有真正修改全局窗口对象。

如何修改Chrome扩展中的全局窗口对象？

解决方案

你不能，不能直接。从内容脚本文档：

< blockquote>

但是，内容脚本有一些限制。它们不能：
$ b

• 使用chrome。* API（除chrome.extension的部分外）


• 使用由其扩展页面定义的变量或函数
  
• 使用由网页或其他内容脚本定义的变量或函数
$ b ul>


（强调增加）
$ b 窗口内容脚本看到的code>对象与页面看到的窗口对象不同。





您可以通过DOM传递消息，但是可以使用 window.postMessage 方法。你的页面和内容脚本都会收听消息事件，并且每当你从其中一个地方调用 window.postMessage 时，另一个会收到它。在内容脚本文档页上有一个这个例子 。



编辑：
您可以通过从内容脚本中注入脚本来向页面添加一些方法。它仍然无法与扩展的其余部分进行通信，而不使用类似于 postMessage 的东西，但是您至少可以将一些内容添加到页面的 window

  var elt = document.createElement（script）; 
 elt.innerHTML =window.foo = {bar：function（）{/ * whatever * /}}; 
 document.head.appendChild（elt）; 
  




I would like to make a Chrome extension that provides a new object inside window. When a web page is viewed in a browser with the extension loaded, I would like window.mything to be available via Javascript. The window.mything object will have some functions that I will define in the extension, and these functions should be callable from console.log or any Javascript file when the page is viewed in a browser with the extension enabled.

I was able to successfully inject a Javascript file into the page by using a Content Script:

var s = document.createElement("script"); 
s.src = chrome.extension.getURL("mything.js");
document.getElementsByTagName("head")[0].appendChild(s);

mything.js looks like this:

window.mything = {thing: true};
console.log(window);

Whenever a page loads, I see the entire window object as I expect it to be in the console. However, I can't interact with the window.mything object from the console. It seems at if the injected script hasn't really modified the global window object.

How can I modify the global window object from a Chrome extension?

解决方案

You can't, not directly. From the content scripts documentation:

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

(emphasis added)

The window object the content script sees is not the same window object that the page sees.

You can pass messages via the DOM, however, by using the window.postMessage method. Both your page and content script listen to the message event, and whenever you call window.postMessage from one of those places, the other will receive it. There's an example of this on the "Content Scripts" documentation page.

edit: You could potentially add some methods to the page by injecting a script from the content script. It still wouldn't be able to communicate back with the rest of the extension though, without using something like postMessage, but you could at least add some things to the page's window

var elt = document.createElement("script");
elt.innerHTML = "window.foo = {bar:function(){/*whatever*/}};"
document.head.appendChild(elt);

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