Where did you install Firefox from? Help Mozilla uncover 3rd party websites that offer problematic Firefox installation by taking part in our campaign. There will be swag, and you'll be featured in our blog if you manage to report at least 10 valid reports!

搜尋 Mozilla 技術支援網站

防止技術支援詐騙。我們絕對不會要求您撥打電話或發送簡訊,或是提供個人資訊。請用「回報濫用」功能回報可疑的行為。

Learn More

JavaScript in firefox.cfg can't access `document`

  • 3 回覆
  • 0 有這個問題
  • 1 次檢視
  • 最近回覆由 jazali

more options

As I understand, `autoconfig.js` (with `firefox.cfg`) can be used to have JavaScript run during startup to control Firefox's UI elements.

I have set up `autoconfig.js` in my `/usr/lib/firefox-developer-edition/defaults/pref` folder (I'm on EndeavourOS Linux). As instructed here, I've already put the two required files, `autoconfig.js` and `firefox.cfg` in their correct folders (`/usr/lib/firefox-developer-edition/defaults/pref` and `/usr/lib/firefox-developer-edition` in my machine).

The file `firefox.cfg` contains the following code:

 //
 (() => {
   var tabbar = document.getElementById("TabsToolbar");
 })();


However, every time I run Firefox, this message will appear:

 "Failed to read the configuration file. Please contact your system administrator."


If I empty out the `firefox.cfg` file, Firefox will run normally without showing the error message. It will also run normally if I just have something like this in the file:

 //
 (() => {
   var testVar = "";
 })();


I don't understand why the JavaScript code can't access the Firefox UI elements through `document` or `window.document`. If `autoconfig.js` isn't build for that, what should I use to change my browser's UI elements through JavaScript?

Thank you.

As I understand, `autoconfig.js` (with `firefox.cfg`) can be used to have JavaScript run during startup to control Firefox's UI elements. I have set up `autoconfig.js` in my `/usr/lib/firefox-developer-edition/defaults/pref` folder (I'm on EndeavourOS Linux). As instructed [https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig here], I've already put the two required files, `autoconfig.js` and `firefox.cfg` in their correct folders (`/usr/lib/firefox-developer-edition/defaults/pref` and `/usr/lib/firefox-developer-edition` in my machine). The file `firefox.cfg` contains the following code: // (() => { var tabbar = document.getElementById("TabsToolbar"); })(); However, every time I run Firefox, this message will appear: "Failed to read the configuration file. Please contact your system administrator." If I empty out the `firefox.cfg` file, Firefox will run normally without showing the error message. It will also run normally if I just have something like this in the file: // (() => { var testVar = ""; })(); I don't understand why the JavaScript code can't access the Firefox UI elements through `document` or `window.document`. If `autoconfig.js` isn't build for that, what should I use to change my browser's UI elements through JavaScript? Thank you.
附加的畫面擷圖

由 jazali 於 修改

被選擇的解決方法

Note that you need a lot more code to be able to access a browser window (i.e. add an observer that is triggered when you open a window).


// start autoconfig.cfg with a comment line
try {
 function ConfigJS() { Services.obs.addObserver(this, 'chrome-document-global-created', false); }
 ConfigJS.prototype = {
  observe: function (aSubject) { aSubject.addEventListener('DOMContentLoaded', this, {once: true}); },
  handleEvent: function (aEvent) {
   let document = aEvent.originalTarget;
   let window = document.defaultView;
   let location = window.location;

   if (/^(chrome:(?!\/\/(global\/content\/commonDialog|browser\/content\/webext-panels)\.x?html)|about:(?!blank))/i.test(location.href)) {
    if (window._gBrowser) { //place your code here
       var tabbar = window.document.getElementById("TabsToolbar");
    }  // gBrowser
   }   // location
  }    // handleEvent
 };    // prototype
 if (!Services.appinfo.inSafeMode) { new ConfigJS(); }
} catch(e) {Cu.reportError(e);}

從原來的回覆中察看解決方案 👍 0

所有回覆 (3)

more options

Did you disable the sandbox via autoconfig.js ?

Content of autoconfig.js:

//start autoconfig.js with a comment line
pref("general.config.filename", "autoconfig.cfg");
pref("general.config.obscure_value", 0);
pref("general.config.sandbox_enabled", false);

有幫助嗎?

more options

選擇的解決方法

Note that you need a lot more code to be able to access a browser window (i.e. add an observer that is triggered when you open a window).


// start autoconfig.cfg with a comment line
try {
 function ConfigJS() { Services.obs.addObserver(this, 'chrome-document-global-created', false); }
 ConfigJS.prototype = {
  observe: function (aSubject) { aSubject.addEventListener('DOMContentLoaded', this, {once: true}); },
  handleEvent: function (aEvent) {
   let document = aEvent.originalTarget;
   let window = document.defaultView;
   let location = window.location;

   if (/^(chrome:(?!\/\/(global\/content\/commonDialog|browser\/content\/webext-panels)\.x?html)|about:(?!blank))/i.test(location.href)) {
    if (window._gBrowser) { //place your code here
       var tabbar = window.document.getElementById("TabsToolbar");
    }  // gBrowser
   }   // location
  }    // handleEvent
 };    // prototype
 if (!Services.appinfo.inSafeMode) { new ConfigJS(); }
} catch(e) {Cu.reportError(e);}

有幫助嗎?

more options

Hi. Thank you very much for the answer! My script can now access `document` thanks to your code. But I'm still confused on how to implement the following into the snipped you provided:

 var tabbar = window.document.getElementById("TabsToolbar");
 function showHideTabbar() {
   var sidebarBox = window.document.getElementById("sidebar-box");
   var sidebarTST = sidebarBox.getAttribute("sidebarcommand");
   if (!sidebarBox.hidden && sidebarTST === "treestyletab_piro_sakura_ne_jp-sidebar-action") {
     tabbar.style.visibility = "collapse";
   }
   else {
     tabbar.style.visibility = "visible";
   }
 }
 var observer = new MutationObserver(showHideTabbar);
 observer.observe(window.document.getElementById("sidebar-box"), { attributes: true, attributeFilter: ["sidebarcommand", "hidden"] });


Its purpose is to hide the tab strip on top when Tree Style Tab is open on the sidebar.

I found that it worked when I ran it through the Browser Toolbox. But it had no effect when I put it into the `if (window._gBrowser) {}` scope. I'm not too familiar with JavaScript, so I can't quite figure out what's wrong.

由 jazali 於 修改

有幫助嗎?

問個問題

如果您還沒有帳號,您必須先登入帳號 來回覆文章。還沒有帳號的話,只能發問新問題