如何从Chrome扩展上下文在页面上运行脚本？

Question

I want to know how I can be disabling the Event Listener "copy"

I think it's something like this:

.js file:

let btn = document.getElementById('btn');

document.body.addEventListener('click', function(e) {
  if (e.target.id === 'btn') {
    e.stopPropagation();
  }
}, {
  capture: false
});

Thanks in advance!

manifest.json:

{
  "name": "Test",
  "version": "1.0",
  "description": "Just testing!",
  "manifest_version": 2,
  "icons": {
    "48": "images/icon_48.png",
    "128": "images/icon_128.png"
  },
  "browser_action": {
    "default_icon": "images/icon_16.png",
    "default_popup": "popup.html"
  }
}

Answer 1

To access the web page you need a content script because the popup is a separate page with its own DOM, document , window , URL, everything.

You also need to intercept the copy event as seen in devtools' event listeners panel:

manifest.json should have the following:

"content_scripts": [{
  "matches": ["https://moller.jusbrasil.com.br/*"],
  "js": ["content.js"],
  "run_at": "document_start"
}]

content.js:

window.addEventListener('copy', e => e.stopImmediatePropagation(), true);

Let's break it down:

1. the content script runs at document_start before any page script
2. addEventListener's third parameter being true means our listener is invoked in the capturing phase of the event dispatch process - before any other standard bubbling phase listener
3. window is the first event target in the capturing phase
4. stopImmediatePropagation() is used because we need both to stop the subsequent bubbling of the event and prevent any other listeners attached by the page script from seeing the event

So the end result is that our listener is guaranteed to be invoked before the page listeners.

PS As you can see there's no need for the browser_action popup for this task.