WebDriver is a remote control interface that enables introspection and control of user agents. As such, it can help developers to verify that their websites are working and performing well with all major browsers. The protocol is standardized by the W3C and consists of two separate specifications: WebDriver classic (HTTP) and the new WebDriver BiDi (Bi-Directional).This newsletter gives an overview of the work we’ve done as part of the Firefox 155 release cycle.

Contributions

Firefox is an open source project, and we are always happy to receive external code contributions to our WebDriver implementation. We want to give special thanks to everyone who filed issues, bugs, and submitted patches. In Firefox 155, several WebDriver bugs were fixed by contributors:

• Khalid AlHaddad updated the Mozilla-specific moz:debugging module to no longer rely on the same nested event loop API as DevTools, which prevents conflicts when WebDriver BiDi and DevTools are used in parallel.
• Nirmal Advani cleaned up our codebase by removing the executeSoon helper, which was just a thin wrapper on top of Services.tm.dispatchToMainThread().
• Nirmal Advani fixed the Actions API so that the dblclick event is fired when performing a double-click while holding down the Ctrl key on non-macOS platforms.
• Sameem added the cleanup logic for subscriptions when a browsing context is destroyed.
• Sameem removed support for the contexts argument in the session.unsubscribe command. From now on, clients can unsubscribe only by event names or subscription ids.

WebDriver code is written in JavaScript, Python, and Rust, so any web developer can contribute! Read how to set up the work environment and check the list of mentored issues for Marionette or the list of mentored JavaScript bugs for WebDriver BiDi. Join our chatroom if you need any help to get started!

All Changes

A complete list of developer-facing changes included in this Firefox release is available in the MDN Firefox 155 Release Notes.