Question 284820 in Javascript Question posted in
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Can't access javascript function from Chrome extension

I’m trying to write a Chrome extension that automates some tasks on my company’s internal website. The website uses .aspx files. I’m trying to call a function __doPostBack() from my extension but I get this error:

test.js:7 Uncaught ReferenceError: __doPostBack is not defined

test.js:

function clickLink() {
  __doPostBack('ctl00$Main$AssetSearchPanel$DialogContainers$GridContainers$ctl02$BtnName','')
}

clickLink()

manifest.json

{
  "manifest_version": 3,
  "name": "Containers v2",
  "description": "Base Level Extension",
  "version": "1.0",
  "content_scripts": [
    {
      "js": [
        "test.js"
      ],
      "matches": [
        "https://url.com"
      ]
    }
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self' 'wasm-unsafe-eval'; object-src 'self';"
  }
}

I tried circumventing calling this function by using inline scripting, but I couldn’t because of Chrome security policy.

I’m able to call the function from the Chrome DevTools console of the page.

Tags:

2

Answers


  1. 0

    I am writing this answer on JavaScript knowledge, and this may not be the case on chrome extensions API or whatever it is called.

    Most of the time, when calling a function from a different file you would have to import or reference the file in your code.

    export function __doPostBack() {
// Your code here

    };

    This is the code you would put in script.js to export your function, and to make it able to be accessible by other files.

    import { __doPostBack } from './script.js';

    This is the code you would put in test.js to import the functions into your file, and to be able to use it

    var test = new __doPostBack()

    Also, you may be able to import your script.js as a library.
    In this case:

    myLibrary.__doPostBack()

    References:
    import function from another JavaScript file

    Note: If there is an answer of someone actually knowing Google chrome extensions, please use their answer.

    Hope this helped you!

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  2. 0

    To solve the problem, you can try the following steps:

    • In the test.js file, make sure to call the __doPostBack function correctly by ensuring that this function matches the URL specified in the manifest.json file. Currently, it seems to match only with https://url.com, so check that this URL is compatible with the target page.

    • If the issue persists, you can update the content_scripts section in the manifest.json file for the test.js file as follows:

      "content_scripts": [
  {
    "js": [
      "test.js"
    ],
    "matches": [
      "https://*.url.com/*"
    ]
  }
]

      This will match with all pages under url.com, including subdomains.

    • Due to Chrome’s security policy, instead of directly calling functions inside, you can communicate through a message. Add the following code to the test.js file:

      chrome.runtime.onMessage.addListener(
  function(request, sender, sendResponse) {
    if (request.action == "callDoPostBack") {
      __doPostBack(request.params);
    }
  }
);

      Then, in the file injecting the content, you can call it like this:

      chrome.runtime.sendMessage({action: "callDoPostBack", params: ['ctl00$Main$AssetSearchPanel$DialogContainers$GridContainers$ctl02$BtnName', '']});
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