How to enable WebGL support in Firefox 4 (Linux)

WebGL is a Web-based Graphics Library. It extends the capability of the JavaScript programming language to allow it to generate interactive 3D graphics within any compatible web browser.
To enable WebGL support in firefox 4 using Ubuntu 10.04 you have to install the library libosmesa6 with the following command:

sudo apt-get install libosmesa6

After this start up firefox and in the url bar type:

about:config

and press enter. Say ok to the alert message and in the search box type "webgl". Double click on "webglosmesalib" parameter and enter the library path (like in the screenshot below).

Enabling Firefox 4 WebGL support.

For me it's:

/usr/lib/libOSMesa.so.6

Now quit and restart Firefox and WebGL support shoul be active.
Enjoy!