Or Frequently Asked Questions...

General FAQ. For the technical FAQ, see the manual.

Why is it not natively headless?
You see windows during the execution of your script? It's normal. Gecko, the rendering engine of Firefox, cannot render web content without a graphical window, until Firefox 56.
You can launch SlimerJS with xvfb if you are under Linux, to have a headless SlimerJS.
The true headless mode is coming with SlimerJS 1.0 and Firefox 57. Try 1.0.0-beta.1!.
What is Gecko?
Gecko is the core engine of Firefox.
Which version of Firefox is SlimerJS compatible with?
It runs with Firefox 50 and some older versions.
Officially, SlimerJS is only compatible with stable versions of Firefox.
Can SlimerJS be executed with unstable version of Firefox?
Yes, if you make some changes. This is explained in the installation manual.
I don't find anymore the "Standalone" edition like for SlimerJS 0.9. Where is it?
There are no more "standalone" edition, since Mozilla has ceased to build and maintain XulRunner. There is only the "lightweight" edition.
Can CasperJS be launched with SlimerJS?
Yes, since SlimerJS 0.8, and with CasperJS 1.1beta1 or higher. Just launch CasperJS as usual by adding --engine=slimerjs on the command line.
Why is it called "SlimerJs"?
Slimer is the name of a ghost in the movie "GhostBusters". As you may know, the Firefox source code uses some references from this movie, and since PhantomJS, CasperJs and other related tools, is a matter of ghosts... ;-)
I found some English errors on the web site or in the documentation
Our apologies for that. English is not the mother tongue of the main author. And he didn't work enough at school in English class :). However, he will be very happy to receive your help to fix English errors. See below how to contribute :-)
How can I contribute?
You can contribute in many ways:
Is there a build of SlimerJS containing the latest improvements?
Yes, each time a bug fix or an improvement is made in the repository of SlimerJS, a build is made. This is we call "nightly build". Since these are development versions don't use them in production.
Download the archive from the stable branch (which contains only latest bug fixes) or from the master branch (which contains latest improvements for the future major release). You can view the documentation from the master branch online here.
Why are there no tests on the WebServer object in the source code?
This module is based on the httpd component of Mozilla used for their own unit tests, and that is already heavily tested
Why are there no tests on the FileSystem object in the source code?
This module is based on the file module provided in the Mozilla Addons SDK, and is already tested.