🦊 Freshly released Firefox 141 comes with a few WebDriver updates. Setup a proxy for a container with browser.createUserContext, monitor history API usage with browsingContext.historyUpdated. And also a few changes around Cookies.

Read more at fxdx.dev/firefox-webd... 🚀

🦊 In Firefox 140, WebDriver BiDi allows to override certificates security settings per container and supports a new "navigationCommitted" event. This release also brings a few fixes for action simulation.

More details at fxdx.dev/firefox-webd... 🚀

State of CSS 2025 is now open: stateofcss.com

Browser vendors use the results of 'State of' surveys to help prioritize the features to work on.

If you care about CSS, please take some time to answer it, and help shape the future of the language

State of CSS 2025 Take the State of CSS survey

The 2025 State of CSS survey is now open! survey.devographics.com/en-US/survey...

Oops, we forgot to share the WebDriver news for Firefox 138!
WebDriver BiDi now lets you install unsigned extensions and allows to set a default viewport for user contexts: fxdx.dev/firefox-webd...

#Firefox #WebDriver #WebDev

Firefox 139 introduces geolocation override via WebDriver BiDi!
Now you can easily test location-aware features: fxdx.dev/firefox-webd...

#Firefox #WebDriver #WebDev

CDP is removed in Firefox 141 in favor of WebDriver BiDi.
For details see fxdx.dev/cdp-retireme...

#Firefox #WebDev

With @firefox.com 138 just around the corner, did you noticed some of the changes we made in 137?
Find out in our latest blog post: fxdx.dev/firefox-devt...

#devtools #html #css #js #network

and since I'm late (as always you might say), you get a bonus post from @juliandescottes.bsky.social talking about the new network request override feature: fxdx.dev/network-over...

Makes it way easier to debug code in prod!

With @firefox.com 138 just around the corner, did you noticed some of the changes we made in 137?
Find out in our latest blog post: fxdx.dev/firefox-devt...

#devtools #html #css #js #network

thanks for the bug, we'll look into it

Bugzilla Main Page

Can you file a bug in bugzilla.mozilla.org ? We'll then run some investigations to check what's happening.
Is the issue only visible when Responsive Design Mode is enabled? Or is this simply related to viewport size?

that's tracked in bugzilla.mozilla.org/show_bug.cgi...

but I don't think there's any short term plan supporting them
(there's an early implementation behind `layout.css.style-queries.enabled` that you can turn on in about:config)

New for WebDriver BiDi in Firefox 137: commands to install/uninstall web extensions, support for containers with event subscriptions and more at fxdx.dev/firefox-webd...

And finally Firefox 136, coming with improved Inspector autocomplete, nested CSS declarations fixes and improved Network monitor: fxdx.dev/firefox-devt...

Let's continue with updates for version 135 which improved WebExtension debugging, added information for CHIPS cookies and provided a new `$$$()` helper in the console: fxdx.dev/firefox-devt...

#firefox #devtools #cookies #webExtensions

Firefox 137 is around the corner and I realized I didn't wrote DevTools release post since the beginning of the year 🫣
Let's start with updates in version 134, which brought a few fixes and some nice accessibility improvements: fxdx.dev/firefox-devt...

#firefox #devtools #js #a11y

New features for WebDriver BiDi in Firefox 136: subscription IDs for better event management and support for containers with preload scripts! More details at fxdx.dev/firefox-webd... 🚀

#Firefox #WebDriver

Cypress 14.1.0 now defaults to WebDriver BiDi for Firefox 135+. A major step in modernizing browser automation!

fxdx.dev/webdriver-bi...

#WebDriverBiDi #Firefox

Geckodriver 0.36.0 is here!
🚀 Improved WebExtension support, precise pointer move actions, better crash handling & fixed WebAuthn endpoints

In Firefox DevTools fonts panel, in the "All Fonts on Page" section, the "Mozilla Headline" font is being used, and some new information are now visible (e.g. Version: 0.100, Designer: Studio DRAMA, …)

We now* display fonts metadata (version, designer, vendor, license, …) in @firefoxdevtools.bsky.social Inspector Fonts panel

* latest @firefoxnightly.bsky.social, 137.0a1 (2025-02-13)

Discover the latest WebDriver updates in Firefox 135 release! Learn about improved user interaction simulations and new screenshot capabilities.

Read more at fxdx.dev/firefox-webd... 🚀

Hard to tell, did you update Windows recently? If so, what was the version you were on before?

I quickly checked and found no difference between today (i.e. Firefox 134) and Firefox 100 (which is quite old already).
Would you be able to use mozilla.github.io/mozregression/ to see when this changed for you?
Also, having the page you're seeing this on and screenshots might help

Couldn't agree more. Of course it is easy for me to say, because I work on browsers already, but when I started at Mozilla, I wrote this post about how working on the browser could really help you become a better web developer: patrickbrosset.com/articles/201...

First WebDriver updates for 2025 with the release of Firefox 134! Checkout the release notes at fxdx.dev/firefox-webd... with a new WebDriver BiDi command for browser windows, additional fields in our network events and better addons support in Marionette.

A screenshot of Firefox DevTools with the "Layout" panel selected shows a visual representation of the shrinking behavior. The element with `flex-shrink: 2` has an initial size of 294px. The item shrinks by 324.75px from the initial size until it reaches the minimum size constraint. The minimum size of its inner content is 45.63px, resulting in a final size of 45.63px.

Overriding the intrinsic minimum size constraint by using `min-width: 0` allows elements to shrink beyond the default limits.

@firefoxdevtools.bsky.social are super helpful to debug such layout issues. They nicely highlight all constraints and make final computed size easy to understand.

The first image is the Firefox error message clearly stating that the host of the test domain is invalid as hostnames can't contain an underscore. While Chrome gives a vague error message.

A good error message makes all the difference!
Shoutout to @firefoxdevtools.bsky.social for saving me from my debugging hell while @googlechrome left me chasing shadows.

Performance and stability are on the menu for the last (and short) newsletter of the year: fxdx.dev/firefox-devt...

#webdev #js #html

We’ve just released a Chrome extension for the Firefox Profiler! 🚀 See how it can enhance your performance workflow in our latest blog post!
blog.mozilla.org/performance/...