We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

firefox.cfg no longer overwrite new tab content

  • 4 replies
  • 4 have this problem
  • 1 view
  • Last reply by sie103

more options

I'm using firefox developer edition. The latest version: 76.0b2 I have firefox.cfg set up to overwrite new tab content with locally stored html. The code in firefox.cfg that worked until recent update:

/* set new tab page */ try {

 var newTabURL = "file:///G:/Documents/Newtab.html";
 aboutNewTabService = Cc["@mozilla.org/browser/aboutnewtab-service;1"].getService(Ci.nsIAboutNewTabService);
 aboutNewTabService.newTabURL = newTabURL;

} catch(e){Cu.reportError(e);} // report errors in the Browser Console

In the browser console there is an error message displayed:

[Exception... "Cannot modify properties of a WrappedNative" nsresult: "0x80570034 (NS_ERROR_XPC_CANT_MODIFY_PROP_ON_WN)" location: "JS frame :: firefox.cfg :: <TOP_LEVEL> :: line 7" data: no]

Any idea what that error message means and how to resolve it? Does anything changed regarding new tab overwrite?

I'm using firefox developer edition. The latest version: 76.0b2 I have firefox.cfg set up to overwrite new tab content with locally stored html. The code in firefox.cfg that worked until recent update: /* set new tab page */ try { var newTabURL = "file:///G:/Documents/Newtab.html"; aboutNewTabService = Cc["@mozilla.org/browser/aboutnewtab-service;1"].getService(Ci.nsIAboutNewTabService); aboutNewTabService.newTabURL = newTabURL; } catch(e){Cu.reportError(e);} // report errors in the Browser Console In the browser console there is an error message displayed: [Exception... "Cannot modify properties of a WrappedNative" nsresult: "0x80570034 (NS_ERROR_XPC_CANT_MODIFY_PROP_ON_WN)" location: "JS frame :: firefox.cfg :: <TOP_LEVEL> :: line 7" data: no] Any idea what that error message means and how to resolve it? Does anything changed regarding new tab overwrite?

Chosen solution

Try this code:

//
var {classes:Cc,interfaces:Ci,utils:Cu} = Components;

/* set new tab page */
try {
  Cu.import("resource:///modules/AboutNewTab.jsm");
  var newTabURL = "file:///G:/Documents/Newtab.html";
  AboutNewTab.newTabURL = newTabURL;
} catch(e){Cu.reportError(e);} // report errors in the Browser Console
Read this answer in context 👍 3

All Replies (4)

more options

Chosen Solution

Try this code:

//
var {classes:Cc,interfaces:Ci,utils:Cu} = Components;

/* set new tab page */
try {
  Cu.import("resource:///modules/AboutNewTab.jsm");
  var newTabURL = "file:///G:/Documents/Newtab.html";
  AboutNewTab.newTabURL = newTabURL;
} catch(e){Cu.reportError(e);} // report errors in the Browser Console

Modified by cor-el

more options

Thank You SO MUCH! This works!

more options

Is there any way to take focus from the address bar? My local page has a search field on it.

more options

This code takes the focus away from the address bar:

// var {classes:Cc,interfaces:Ci,utils:Cu} = Components; try {

 Cu.import("resource:///modules/AboutNewTab.jsm");  
 var newTabURL = "file:///D:/Dox/Startseite/Startseite.htm";  
 AboutNewTab.newTabURL = newTabURL;  

} catch(e){Cu.reportError(e);} // report errors in the Browser Console

// Optional: Don't place the caret in the location bar. Useful if you want a page's search box to have focus instead. function SetFocusOnPage () {

 setTimeout(function() {
 gBrowser.selectedBrowser.focus();
 }, 0);

} gBrowser.tabContainer.addEventListener("TabOpen", SetFocusOnPage, false);