tabs API does not support filters?

[webcoding123]

MDN URL

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Background_scripts

What specific section or headline is this issue about?

Filter events

What information was incorrect, unhelpful, or incomplete?

If an extension is listening for tabs.onUpdated, use the webNavigation.onCompleted event with filters instead, as the tabs API does not support filters.

What did you expect to see?

tabs.onUpdated support filters.

Do you have any supporting links, references, or citations?

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/onUpdated

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/mozilla/add-ons/webextensions/background_scripts
• MDN URL: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Background_scripts
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/mozilla/add-ons/webextensions/background_scripts/index.md
• Last commit: 3819942
• Document last modified: 2026-05-15T16:16:56.000Z

[rebloor]

@Rob--W @bacharakis @mixedpuppy we added the background script page in #15533 and according to the BCD for tabs.onUpdated filtering has been supported since Firefox 61. I can't see where we source this information, but I'm wondering if there's a nuance missing from the comment. For example, given that filtering is only supported in Firefox desktop, could this have been intended as a note on cross-platform extension development?

[Rob--W]

For example, given that filtering is only supported in Firefox desktop, could this have been intended as a note on cross-platform extension development?

The note in the issue is a suggestion, not an existing note. Given the limited support (Firefox desktop only), I think that it is worth mentioning the limited support and webNavigation as an alternative. Do include a warning that the webNavigation API requires the webNavigation permission that triggers a permission warning (the tabs.onUpdated API can be used to filter on events with the tabs permission (also triggering a permission warning) or without tabs permission (provided that host permissiond have been granted). For observing tabs whose URLs are already in host permissions, this difference in permission requirements may deter a switch to the webNavigation API.