None of the issues I found are up to date or specific to my case.

I was following this tutorial https://www.youtube.com/watch?v=0n809nd4Zu4&ab_channel=freeCodeCamp. But, I adapted the code to fit what I needed.

For my background.js I followed what the tutorial did in determining whether a new URL was loaded.

// background.js
chrome.tabs.onUpdated.addListener((tabId, tab) => {
  if (tab.url && tab.url.includes("ebay.com/sch")) {
    const queryParameters = tab.url.split(/3&_/)[1];
    console.log(queryParameters)
    const urlParameters = new URLSearchParams(queryParameters);

    chrome.tabs.sendMessage(tabId, {
      type: "NEW",
      searchID: urlParameters.get("nkw")
    });
  }
})

However I get the error in console Uncaught (in promise) Error: Could not establish connection. Receiving end does not exist.

In the content script file I have

// contentScript.js
chrome.runtime.onMessage.addListener((obj, sender, response) => {
        const { type, value, searchId } = obj;
        console.log(type)
        if (type === "NEW") {
            currentSearch = searchId
            newSearchLoaded();
        }
    });

// manifest.json
{
    "name": "eBay Listing Remover",
    "version": "0.1.0",
    "description": "Remove unwanted eBay listings from search.",
    "permissions": ["storage", "tabs"],
    "host_permissions": ["https://*.ebay.com/*"],
    "background": {
      "service_worker": "background.js"
    },
    "content_scripts": [
      {
        "matches": ["https://*.ebay.com/*"],
        "js": ["contentScript.js"]
      }
    ],
    "web_accessible_resources": [
      {
        "resources": [
          "assets/bookmark.png",
          "assets/play.png",
          "assets/delete.png",
          "assets/save.png"
        ],
        "matches": ["https://*.ebay.com/*"]
      }
    ],
    "action": {
      "default_icon": {
        "16": "assets/ext-icon.png",
        "24": "assets/ext-icon.png",
        "32": "assets/ext-icon.png"
      },
      "default_title": "My YT Bookmarks",
      "default_popup": "popup.html"
    },
    "manifest_version": 3
}

Edit:

Updated manifest.json

{
    "name": "eBay Listing Remover",
    "version": "0.1.0",
    "description": "Remove unwanted eBay listings from search.",
    "permissions": ["storage", "tabs"],
    "host_permissions": ["https://*.ebay.com/*"],
    "background": {
      "service_worker": "background.js"
    },
    "content_scripts": [
      {
        "matches": ["https://*.ebay.com/*"],
        "run_at": "document_end",
        "js": ["contentScript.js"]
      }
    ],
    "web_accessible_resources": [
      {
        "resources": [
          "assets/bookmark.png",
          "assets/play.png",
          "assets/delete.png",
          "assets/save.png"
        ],
        "matches": ["https://*.ebay.com/*"]
      }
    ],
    "action": {
      "default_icon": {
        "16": "assets/ext-icon.png",
        "24": "assets/ext-icon.png",
        "32": "assets/ext-icon.png"
      },
      "default_title": "My YT Bookmarks",
      "default_popup": "popup.html"
    },
    "manifest_version": 3
}

Updated background.js

chrome.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
  if (changeInfo.status === "complete" && tab.url && tab.url.includes("ebay.com/sch")) {
    const queryParameters = tab.url.split(/3&_/)[1];
    console.log(queryParameters)
    const urlParameters = new URLSearchParams(queryParameters);

    chrome.tabs.sendMessage(tabId, {
      type: "NEW",
      searchID: urlParameters.get("nkw")
    });
  }
})

CodePudding user response：

// background.js
chrome.tabs.onUpdated.addListener((tabId, changedInfo, tab) => {
  if (changeInfo.status === "complete" && tab.url && tab.url.includes("ebay.com/sch")) {
    const queryParameters = tab.url.split(/3&_/)[1];
    console.log(queryParameters)
    const urlParameters = new URLSearchParams(queryParameters);

    chrome.tabs.sendMessage(tabId, {
      type: "NEW",
      searchID: urlParameters.get("nkw")
    });
  }
})

Please try this code. Also, please change the run_at to document_end in manifest.json