Can I ask if there will be the possibility to integrate that script here in this forum (without using an external extension)? Thanks for the attention.
One way would be to create a forum theme that contains my script. That way it's available to every user and can be enabled/disabled from the user control panel. You'll have to petition theymos to do that though.
Another way (which I mentioned before), would be to use a proxy that injects the script.