Where/how do I run the script pkcs11.installModule()?

Complete noob to managing FF, and I need to script setup a security device for users. Is this something that would be run as a script by the user like a logon script. or something that would be added to the website the user is accessing?

thanks.

This would be ran part of an extension, so it would be something that the user has to install, or their enterprise deployment installs - though I think enterprise deployments can directly add pkcs11 modules.