Load JS File from relative dir instead of absolute url

Hi everybody and merry christmas.

Problem:

I have a dir on my server with all important files (PHP CLASSES, FUNCTIONS etc.) to use for more than one of my Domains / Sites. (Dosen't make sense to me to copy same files for and to each domain folder, so i go this way). PHP works like a charm. But than i need to load a couple JS Files to from this folder to include in my site.

Instead of <script src="http://mydomain.com/scripts/myjsfile.js"> i need something like this <script src="/root/client/mainfiles/scripts/myjsfile.js">

Isn't working. Maybe because of security reasons?

It always searches for my file by GET http://mydomain.com/root/client/main...ts/myjsfile.js

Is there someone out there how know how to fix it?