Today Mozilla released Firefox 40. We just just deployed it to all Browserling's OS platforms. You can already cross-browser test your websites and JS code in Firefox 40!

Cross-browser testing in Firefox 40

Try Firefox 40 in Browserling now!

The new Firefox 40 features include:

  • Support for Windows 10.
  • Added protection against unwanted software downloads.
  • User can receive suggested tiles in the new tab page based on categories Firefox matches to browsing history (en-US only).
  • Hello allows adding a link to conversations to provide context on what the conversation will be about.
  • New style for add-on manager based on the in-content preferences style.
  • Improved scrolling, graphics, and video playback performance with off main thread compositing (GNU/Linux only).
  • Graphic blocklist mechanism improved: Firefox version ranges can be specified, limiting the number of devices blocked.

Firefox 40 biggest changes include:

  • Add-on extensions that are not signed by Mozilla will display a warning.
  • NPAPI Plug-in performance improved via asynchronous initialization.
  • Smoother animation and scrolling with hardware vsync (Windows only).
  • JPEG images use less memory when scaled and can be painted faster.
  • Sub-resources can no longer request HTTP authentication, thus protecting users from inadvertently disclosing login data.

Firefox 40 HTML5 updates include:

  • IndexedDB transactions are now non-durable by default.
  • Implemented AudioBufferSourceNode.detune to modulate playback rate in cents, a logarithmic unit of measure used for musical intervals.

Firefox 40 developer tool updates include:

  • Improved Performance tools in the developer tools: Waterfall view, Call Tree view and a Flame Chart view.
  • New rules view tooltip in the Inspector to tweak CSS Filter values.
  • Console API messages from SharedWorker and ServiceWorker are now displayed in web console.
  • New page ruler highlighting tool that displays lightweight horizontal and vertical rules on a page.
  • Inspector now searches across all content frames in a page.

Firefox 40 fixes include:

  • Kannada text does not display properly in built-in pdf viewer.
  • Various security fixes.

Firefox 40 security fixes include:

  • Use-after-free in XMLHttpRequest with shared workers.
  • Mozilla Content Security Policy allows for asterisk wildcards in violation of CSP specification.
  • Vulnerabilities found through code inspection.
  • Buffer overflows on Libvpx when decoding WebM video.
  • Heap overflow in gdk-pixbuf when scaling bitmap images.
  • Crash when using shared memory in JavaScript.
  • Feed protocol with POST bypasses mixed content protections.
  • Out-of-bounds write with Updater and malicious MAR file.
  • Arbitrary file overwriting through Mozilla Maintenance Service with hard links.
  • Overflow issues in libstagefright.
  • Redefinition of non-configurable JavaScript object properties.
  • Use-after-free in MediaStream playback.
  • Out-of-bounds read with malformed MP3 file.
  • Miscellaneous memory safety hazards (rv:40.0 / rv:38.2).

Happy cross-browser testing in Firefox 40!