userAgent.extra

[slackhead]

Hi all, I'm trying to set window.navigator.userAgent.extra.slackware to 'slackware' but I just get an error:

Uncaught TypeError: Cannot set property 'slackware' of undefined

What do I need to do to add .extra.slackware and set it?

[kubas]

there is no such property in object userAgent

[slackhead]

In firefox it is possible to make this work by creating an entry in about:config. This is for the linuxquestions.org website to make an icon appear showing your distro.

Is it possible to create this property in javascript?