Development

Topic	Replies	Views	Activity
Get started with Firefox extension development Extensions provide a simple and powerful way to personalize your browsing experience. If you know JavaScript, CSS, and HTML, you can build your own. If you are brand-new to add-on development, you can get started by che…	6	17425	September 30, 2025
About the Development category	0	4545	May 21, 2015
Unexpected tab group auto-joining behavior after `browser.tabs.move` call issue	3	55	March 5, 2026
Host permissions lost on extension upgrade of enterprise installed extension	0	35	February 23, 2026
Hide developer email address	1	34	February 19, 2026
Borderify Extension not working (no errors) learning , development	9	2451	February 14, 2026
Questions about including third-party libraries	1	37	February 10, 2026
How does Mozilla calculate daily users in the statistics panel?	1	59	February 10, 2026
Is there a way to stream in-memory data into downloads.download? learning	0	27	February 9, 2026
Feedback wanted: Selenium WebExtension Bridge for Firefox feedback	0	25	February 8, 2026
Selection changed event behaviour changed since 148? issue	0	34	February 7, 2026
Proper way to create an add-on for internal use	1	33	February 6, 2026
Intercepting HTTP requests doesn't work	2	24	February 6, 2026
Adding onUserScriptConnect / onUserScriptMessage listeners	0	20	January 23, 2026
Is Firefox MV3 intentionally not supporting `browser.runtime.onMessage` in MV3 userScripts API? Why?	8	159	January 21, 2026
Why does runtime.onSuspend not execute window.localStorage.setItem? learning , issue	2	27	January 19, 2026
How to automate add-on option screen tests?	7	225	December 30, 2025
Firefox Default Themes & Theme Values	2	52	December 24, 2025
Insert text into textbox with add-on click learning	2	90	December 15, 2025
How to prevent redirecting to HTTPS when fetching local address from a background script?	2	43	December 3, 2025
Do older Firefox versions ignore "data_collection_permissions"?	2	223	December 3, 2025
A way to set tab context as default for new tab	3	100	November 18, 2025
[EDITED] Error: Permission denied to access property "then" issue , manifest-v3	4	2226	November 18, 2025
Funcions `loadOneTab` and `loadURI` in 2023 in Firefox Experimental API?	2	698	November 16, 2025
Foucs behavior issue on sidebar when opening	1	44	October 29, 2025
Pin Tab Enhancement / Side Bar Control	2	321	October 25, 2025
[Manifest V3] background script stopped when signed extension is up	3	84	October 15, 2025
WebExtension API support for web app windows	3	103	October 10, 2025
IDEA - Add Unsubscribe Footer thunderbird	0	37	October 5, 2025
Validation says data_collection_permissions missing, but exists in manifest? issue	2	1296	September 20, 2025

Get started with Firefox extension development

Extensions provide a simple and powerful way to personalize your browsing experience. If you know JavaScript, CSS, and HTML, you can build your own. If you are brand-new to add-on development, you can get started by che…