How to use JavaSript library stored in mime type repository???

Hi Experts

I currently have the situation that I would like to deploy several JavaScript functions in a multitude of templates. I need my own JavaScript functions as the provided functionality is not sufficient.

I have figured that I can add my function by using the script item and that works fine, but it requires the script to be entered in every template.

My idea is to store the central JS file in the mime type repository and then reference it, however it doesn't seem to work.

Does anybody have an idea on how to make it work or alternatively have a central JavaScript library that is used by several different templates?

Thanks for your help, regards,

Minima