Firefox Beta

December 4, 2014

Version 35.0beta, first offered to Beta channel users on December 4, 2014


  • Firefox Hello with new rooms-based conversations model

  • Built-in support for H264 (MP4) on Mac OS X Snow Leopard (10.6) and newer through native APIs

  • Improved handling of dynamic styling changes to increase responsiveness


  • Show DOM Properties context menu item in inspector

  • Reduced resource usage for scaled images

  • PDF.js updated to version 1.0.907


  • Developer Information
  • Support for inspecting ::before and ::after pseudo elements

  • Computed view: Nodes matching the hovered selector are now highlighted

Web Platform

  • Changed JavaScript 'let' semantics to conform better to the ES6 specification

  • Resource Timing API implemented

  • CSS filters enabled by default

  • WebSocket now available in Web Workers

  • Added support for the CSS Font Loading API

All Firefox Beta downloads