Add JavaScript to all pages across solution

Hi,

I'd like to add a piece of JavaScript to my Dynamics CRM environment.

That means, that by loading any page on my Dynamics portal, I want that JavaScript to be part of the HTML-source.

From a concept view, it's comparable to what you have to do to get Google Analytics in.

All options that I found so far by research would require me to add that custom piece of HTML to lots of different elements. But there has to be an option to modify as few elements as possible, right?

What's the best approach to do this? Would you recommend a client-side or a server-side approach?

Thanks in advance, any feedback highly appreciated!

Martin