Firefox OS 1.4 is at a pre-release stage right now. Its Gecko component is based on Firefox 30 (see Firefox 30 release notes for developers.) This page details the developer features newly implemented in Firefox OS 1.4.


Gecko general:


SpiderMonkey general:


Firefox OS specific:

Gecko general:


Gecko general:


  • The precompile manifest field is now supported, which specifies that asm.js code contained within the app should be compiled at install time, install of during first run.

See also

Older versions


Document Tags and Contributors

Contributors to this page: chrisdavidmills, ccarruitero, teoli, fscholz, NickDesaulniers
Last updated by: chrisdavidmills,