javascript Chrome 扩展 - 获取 DOM 内容
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Chrome Extension - Get DOM content
提问by brandonhilkert
I'm trying to access the activeTab DOM content from my popup. Here is my manifest:
我正在尝试从弹出窗口访问 activeTab DOM 内容。这是我的清单：
{
"manifest_version": 2,
"name": "Test",
"description": "Test script",
"version": "0.1",
"permissions": [
"activeTab",
"https://api.domain.com/"
],
"background": {
"scripts": ["background.js"],
"persistent": false
},
"content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
"browser_action": {
"default_icon": "icon.png",
"default_title": "Chrome Extension test",
"default_popup": "index.html"
}
}
I'm really confused whether background scripts (event pages with persistence: false) or content_scripts are the way to go. I've read all the documentation and other SO posts and it still makes no sense to me.
我真的很困惑后台脚本（具有持久性的事件页面：false）还是 content_scripts 是要走的路。我已经阅读了所有文档和其他 SO 帖子，但对我来说仍然没有任何意义。
Can someone explain why I might use one over the other.
有人可以解释为什么我可能会使用一个而不是另一个。
Here is the background.js that I've been trying:
这是我一直在尝试的 background.js：
chrome.extension.onMessage.addListener(
function(request, sender, sendResponse) {
// LOG THE CONTENTS HERE
console.log(request.content);
}
);
And I'm just executing this from the popup console:
我只是从弹出式控制台执行此操作：
chrome.tabs.getSelected(null, function(tab) {
chrome.tabs.sendMessage(tab.id, { }, function(response) {
console.log(response);
});
});
I'm getting:
我越来越：
Port: Could not establish connection. Receiving end does not exist.
UPDATE:
更新：
{
"manifest_version": 2,
"name": "test",
"description": "test",
"version": "0.1",
"permissions": [
"tabs",
"activeTab",
"https://api.domain.com/"
],
"content_scripts": [
{
"matches": ["<all_urls>"],
"js": ["content.js"]
}
],
"content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
"browser_action": {
"default_icon": "icon.png",
"default_title": "Test",
"default_popup": "index.html"
}
}
content.js
内容.js
chrome.extension.onMessage.addListener(
function(request, sender, sendResponse) {
if (request.text && (request.text == "getDOM")) {
sendResponse({ dom: document.body.innerHTML });
}
}
);
popup.html
弹出窗口.html
chrome.tabs.getSelected(null, function(tab) {
chrome.tabs.sendMessage(tab.id, { action: "getDOM" }, function(response) {
console.log(response);
});
});
When I run it, I still get the same error:
当我运行它时，我仍然收到相同的错误：
undefined
Port: Could not establish connection. Receiving end does not exist. lastError:30
undefined
回答by gkalpak
The terms "background page", "popup", "content script" are still confusing you; I strongly suggest a more in-depth look at the Google Chrome Extensions Documentation.
术语“背景页面”、“弹出窗口”、“内容脚本”仍然让您感到困惑；我强烈建议更深入地查看Google Chrome 扩展文档。
Regarding your question if content scripts or background pages are the way to go:
关于您的问题，内容脚本或背景页面是否可行：
Content scripts: Definitely
Content scripts are the only component of an extension that has access to the web-page's DOM.
内容脚本：当然，
内容脚本是扩展程序中唯一可以访问网页 DOM 的组件。
Background page / Popup: Maybe (probably max. 1 of the two)
You may need to have the content script pass the DOM content to either a background page or the popup for further processing.
后台页面/弹出窗口：可能（最多可能是两者中的 1 个）
您可能需要让内容脚本将 DOM 内容传递给后台页面或弹出窗口以进行进一步处理。
Let me repeat that I strongly recommend a more careful study of the available documentation!
That said, here is a sample extension that retrieves the DOM content on StackOverflow pages and sends it to the background page, which in turn prints it in the console:
让我重复一遍，我强烈建议对可用文档进行更仔细的研究！
也就是说，这是一个示例扩展，它检索 StackOverflow 页面上的 DOM 内容并将其发送到后台页面，后台页面又将其打印在控制台中：
background.js:
背景.js：
// Regex-pattern to check URLs against.
// It matches URLs like: http[s]://[...]stackoverflow.com[...]
var urlRegex = /^https?:\/\/(?:[^./?#]+\.)?stackoverflow\.com/;
// A function to use as callback
function doStuffWithDom(domContent) {
console.log('I received the following DOM content:\n' + domContent);
}
// When the browser-action button is clicked...
chrome.browserAction.onClicked.addListener(function (tab) {
// ...check the URL of the active tab against our pattern and...
if (urlRegex.test(tab.url)) {
// ...if it matches, send a message specifying a callback too
chrome.tabs.sendMessage(tab.id, {text: 'report_back'}, doStuffWithDom);
}
});
content.js:
内容.js：
// Listen for messages
chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
// If the received message has the expected format...
if (msg.text === 'report_back') {
// Call the specified callback, passing
// the web-page's DOM content as argument
sendResponse(document.all[0].outerHTML);
}
});
manifest.json:
清单.json：
{
"manifest_version": 2,
"name": "Test Extension",
"version": "0.0",
...
"background": {
"persistent": false,
"scripts": ["background.js"]
},
"content_scripts": [{
"matches": ["*://*.stackoverflow.com/*"],
"js": ["content.js"]
}],
"browser_action": {
"default_title": "Test Extension"
},
"permissions": ["activeTab"]
}
回答by Oskar
You don't have to use the message passing to obtain or modify DOM. I used chrome.tabs.executeScriptinstead. In my example I am using only activeTab permission, therefore the script is executed only on the active tab.
您不必使用消息传递来获取或修改 DOM。我用了chrome.tabs.executeScript。在我的示例中，我仅使用 activeTab 权限，因此脚本仅在活动选项卡上执行。
part of manifest.json
manifest.json 的一部分
"browser_action": {
"default_title": "Test",
"default_popup": "index.html"
},
"permissions": [
"activeTab",
"<all_urls>"
]
index.html
索引.html
<!DOCTYPE html>
<html>
<head></head>
<body>
<button id="test">TEST!</button>
<script src="test.js"></script>
</body>
</html>
test.js
测试.js
document.getElementById("test").addEventListener('click', () => {
console.log("Popup DOM fully loaded and parsed");
function modifyDOM() {
//You can play with your DOM here or check URL against your regex
console.log('Tab script:');
console.log(document.body);
return document.body.innerHTML;
}
//We have permission to access the activeTab, so we can call chrome.tabs.executeScript:
chrome.tabs.executeScript({
code: '(' + modifyDOM + ')();' //argument here is a string but function.toString() returns function's code
}, (results) => {
//Here we have just the innerHTML and not DOM structure
console.log('Popup script:')
console.log(results[0]);
});
});
回答by bxN5
For those who tried gkalpak answer and it did not work,
对于那些尝试过 gkalpak 回答但没有用的人，
be aware that chrome will add the content script to a needed page only when your extension enabled during chrome launch and also a good idea restart browser after making these changes
请注意，仅当您在 chrome 启动期间启用扩展程序时，chrome 才会将内容脚本添加到所需页面，并且在进行这些更改后重新启动浏览器也是一个好主意
