Firefox 110 for developers

This article provides information about the changes in Firefox 110 that will affect developers. Firefox 110 was released on February 14, 2023.

Changes for web developers


No notable changes.





  • CSSContainerRule is supported, allowing JavaScript to access the name and query used in an @container at-rule definition (Firefox bug 1787173).
  • Elements now lose focus if a style is applied that makes them ineligible to hold focus, such as hidden, and the blur event is fired. Focus then moves to the viewport. Previously focus would remain with the element. (See Firefox bug 1810077 for more details.)

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi


  • The cache for known nodes (element and shadow root references) has been moved from the parent to the web content process following recent WebDriver classic changes (Firefox bug 1692468).
  • Improved the JSON serialization and deserialization algorithms to be compliant with the WebDriver classic specification (Firefox bug 1794078).

Changes for add-on developers

Older versions