I’m trying to make an extension that copies the selected text on a web page and sends it to an extension popup. I followed this but its not working, its throwing these errors instead:

Here’s my files and code:
manifest.json

    "manifest_version": 3,
    "name": "Test",
    "description": "...",
    "version": "0.1",
    "action": {
        "default_popup": "popup.html",
        "default_icon": "icon.png",
        "default_title": "Test"
    },
    "permissions": [
        "tabs"
    ],
    "host_permissions": [
        "<all_urls>"
    ],
    "content_scripts": [
        {
          "matches": ["<all_urls>"],
          "js": ["scripts/selection.js"],
          "run_at": "document_start",
          "all_frames": true
        }
    ]
}

scripts/popup.js

$(function(){
    $('#paste').click(function(){
        pasteSelection();
    });
});

function pasteSelection() {
    chrome.tabs.query({
        active:true, windowId: chrome.windows.WINDOW_ID_CURRENT
    }, function(tab) {
        chrome.tabs.sendMessage(tab[0].id, {method: "getSelection"}, 
        function(response){
            var text = document.getElementById('text'); 
            text.innerHTML = response.data;
        });
    });
}

scripts/selection.js

chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if (request.method == "getSelection")
      sendResponse({data: window.getSelection().toString()});
    else
      sendResponse({}); // snub them.
  });

I reloaded the extension after I added the code. Opened a wikipedia page, selected some text, and clicked on the extension. and right away the errors came in. I tried clicking the “Paste Selection” button aswell. but it did nothing, it just sent the same errors again.