I have created my Web Extension for Firefox which uses Chrome Extension API. But Firefox requires application key in manifest.json https://developer.mozilla.org/en-US/Add-ons/WebExtensions/manife...

I need to modifiy a html page with javascript (fill a field). I have a specific url but i do not know how to listen when the browser is on the right url and get the html code associate. I do it wi...

I wonder if it is possible to use WebAssembly to develop an add-on for Firefox. I doubt that it is possible to do completely in WASM, but what about WASM core with minimal JavaScript wrapper?

Note - this question is based off of this question (although it's not necessary to read the previous question): How to set value of textarea in different HTML file? I have the following code, whic...

I was trying to write a simple extension in Firefox wherein I modify the X-Frame-Allow header. I looked at the documentation briefly and I see that they support webRequest.onHeadersReceived.addLis...

When attempting to use a library with a source map from within a WebExtension, I encounter this error. Source map error: TypeError: NetworkError when attempting to fetch resource. Resource URL: mo...

I'm trying to write a simple Web Extension. Currently I'm following the various tutorials and trying to understand the architecture. Interaction with specific tabs is done with content_scripts tha...

In a web-extension, I'm registering a content-script programmatically: browser.contentScripts.register({ matches: ["https://www.example.com/messages/*"], js: [{file: "my-callback-script"}], run...

It seems Chrome doesn't have an API to open the popup, but has a dedicated system for doing it with a hotkey: _execute_browser_action key in commands. The special functionality of _execute_browser...

I was having trouble finding an up-to-date answer for this issue, and don't often have time to answer questions here so thought I'd post this so I can answer my own question since I figured out a s...

Google Chrome contains some functionality in its chrome.webrequest API (e.g., http://developer.chrome.com/extensions/samples.html#12a7bf1490a26359eadf10917e37c5b9 ) that can be used to redirect ce...

I released a new version of a firefox webextension, Copy All Tabs last night. The code is open source and available on github. The new version fixes many bugs and is overall more stable. It works...

I'm writing a web extension works on firefox. I want my icon works similar to the behavior of Firefox built in "Take a screenshot". The screenshot icon appeared in different colors when it shown in...

I am new to FF extensions development. I work on Windows OS. I am using web extensions. I started my first extension. I created a directory in My Documents which contains my extension files. The fi...

I'm trying to execute a script in a new tab when that tab is opened. In my background script I have: var listener = function (tab) { browser.tabs.executeScript(null, { file: "content_scripts/con...

I would like to create a WebExtension that provides toggle buttons for some of the settings in about:config (e.g. permissions.default.image). Is it possible to do this in WebExtensions? If so, ...

I want to use Cognito for my WebExtension for Chromium and Firefox. I have two problems. 1) Hosted UI from Cognito not at my domain - so users may think why: For branding and security I want t...

I am building a chrome/firefox web extension. When the user clicks the button in the extension's popup, the extension's UI changes. Here's a visual example: Before pressing one of three buttons...

I'm trying to use a shared vue.js state in a web extension. The state is stored in the background script's DOM and rendered in a popup page. First attempt My first attempt was to use a simple st...

I am trying to code a simple firefox extension that displays the title of the current tab the user is viewing when the extension's button is pressed. Here is my manifest.json file: { "manife...

If you make a fetch request in a Firefox WebExtension, it will automatically set the "origin" header. For example, when I run this code inside a WebExtensions ... fetch('http://example.com/') .....

I'm having a hard time debugging my Firefox extension (popup). Whenever I click on the debug pane, the popup closes and all the information in the debug pane is gone. This happens when trying to in...

During development of my browser extension I faced with that error. What it could be? I found this message in the source code of Firefox: getContextById(childId) { let context = this.proxy...

I am creating a web extension to help detecting postMessage activity in websites. Therefore, I want to detect it when a page attaches a message event listener, for example by calling this code: wi...

i am a little new at this. Please help I am trying to return a promise from a function. This seems to work well until I try to return the promise in the then of an existing promise. I am trying t...