SlimerJS runs on any platform on which Firefox or XulRunner is available: Linux (32bits and 64bits), Windows, MacOs X. XulRunner is the core of Firefox without its user interface.

On windows, you should open a terminal. You can use the classical cmd.exe, or the recent PowerShell.exe. You can also install Cygwin and use its terminal.

You cannot use the MingW32 environment on Windows because there are some issues with (no output in the console, and it lacks on some commands like mktemp).

On Linux, standalone editions need these libraries:,,,,,,,,, On Ubuntu/Debian, you can install/verify it by doing:

sudo apt-get install libc6 libstdc++6 libgcc1 libgtk2.0-0 libasound2 libxrender1

Installation of SlimerJS

To install SlimerJS, you need to download its package. It is available in two editions:

  • The Standalone Edition: this is a zip/gz package containing SlimerJS and XulRunner. There is a package for each operating system. Download it, extract it. Everything is here. You’re ready to use SlimerJS. Go to the Lauching SlimerJS section.
  • The Lightweight Edition: this is a zip package containing only SlimerJS and it targets all operating system. You have to install Firefox or XulRunner separately (version 25 is recommanded) and probably you’ll need to set an environment variable. This package can be downloaded from Or it can be installed from a repository like the Arch Linux’s repository or Homebrew.

See the download page to know the places from where you can retrieve SlimerJS.

Configuring SlimerJS

During its launch, SlimerJS tries to discover itself the path of Firefox or XulRunner. This is not a problem for the Standalone edition or linux packages.

In case it fails (this could be the case for the lightweight edition), or if you want to launch SlimerJS with a specific version of Firefox, you should create an environment variable containing the path of the Firefox/XulRunner binary. To create this environment variable from a command line:

  • On linux:
    export SLIMERJSLAUNCHER=/usr/bin/firefox
  • on Windows
    SET SLIMERJSLAUNCHER="c:\Program Files\Mozilla Firefox\firefox.exe
  • On windows with cygwin
    export SLIMERJSLAUNCHER="/cygdrive/c/program files/mozilla firefox/firefox.exe"
  • On MacOS
    export SLIMERJSLAUNCHER=/Applications/

You can of course set this variable in your .bashrc, .profile or in the computer properties on Windows.

An alternative on linux or macos, is to create a link to an installed xulrunner package. Go into the SlimerJS directory and type for example:

ln -s /usr/lib/xulrunner

The path could change, depending of where Xulrunner is installed.

Using unstable version or very old versions of Firefox/XulRunner

By default, SlimerJS is configured to be compatible only with specific stable versions of Firefox and XulRunner. It’s because internal API of Firefox/XulRunner can be changed between versions, and so SlimerJS may not work as expected. Stranges behaviors or even fatal errors may appears with unsupported versions. SlimerJS has only been tested with specific versions of Firefox/XulRunner.

However, you can change this limitation, by modifying the maxVersion parameter (and/or the minVersion) in the application.ini of SlimerJS. But remember you do it at your own risk.

If you found issues with unsupported versions of Firefox/XulRunner, please discuss about it in the mailing-list, especially if it is about unstable version fo Firefox/XulRunner.

Launching SlimerJS

From a command line, call the slimerjs executable (or slimerjs.bat for Windows) with the path of a javascript file.

/somewhere/slimerjs-1.2.3/slimerjs myscript.js
# or if SlimerJS is in your $PATH:
slimerjs myscript.js

On Windows:

c:\somewhere\slimerjs-1.2.3\slimerjs.bat myscript.js

The js script should contain your instructions to manipulate a web page...

You can indicate several options on the command line. See the “configuration” chapter.

Having a headless SlimerJS

There is a tool called xvfb, available on Linux and MacOS. It allows to launch any “graphical” programs without the need of an X-Windows environment. Windows of the application won’t be shown and will be drawn only in memory.

Install it from your prefered repository (sudo apt-get install xvfb with debian/ubuntu).

Then launch SlimerJS like this:

xvfb-run ./slimerjs myscript.js

You won’t see any windows. If you have any problems with xvfb, see its documentation.

Using flash plugin or other kind plugins

SlimerJS is able to load Flash content if the Flash plugin is installed, and is able to load any other plugins.

In fact, every NPAPI plugins that work with any browser can be used by SlimerJS. Just install them as indicated by the vendor, and it will be theorically recognized by SlimerJS. See details on MDN .

For example, on linux, install the corresponding package. However, in some case, you should probably use the xulrunner or the Firefox package of the distro, instead of the xulrunner provided by SlimerJS. This is apparently the case for Fedora for example.

Note: plugins are not Firefox/XUL/JS extensions. Plugins and “extensions” are two different things in the gecko world. Extensions for Firefox are pieces of code to extends some features of Gecko and/or to add some UI things in the interface of Firefox. Plugins are black boxes that can only be loaded with the html element <object>, like Flash.

See detailed definition of plugins on MDN .

Creating extensions?

Theorically, you can create XUL/JS extensions for SlimerJS like you do for Firefox, but their installation is not easy since their are no user interface to install them. However, it is theorically possible to create and install extensions.

See documentation on MDN.