Question about including a GPL script

Question

I am migrating a client's static website, which was done by another company, to our (propietary) CMS.

On their website thay have a small slideshow that is powered by a JavaScript library that is licensed under GPL. The attached license notice is below:

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

Now I don't know a lot about the GPL and have not used GPL code on a website before. If I include this library in the website what obligations do I have? Would I be required to release the server side code of the CMS? Since the HTML output is freely accessible via the Page Source is this sufficent to satisfy the GPL?

The code is remaining on our servers so the code is not being distributed, not even to the client (customer).

UPDATE: Based on the comment by mgb and the fact this is clientside JavaScript then the GPL code is being distributed. What do I do to comply with the GPL then?

Thanks for your advice.

Answer 1

It's a slightly contentious area.

If you are only using it server-side then under GPL (but not AGPL) you aren't distributing it so don't have to do anything.

If it's used client side then you are already distributing the source in the html.

edit: There is a purist element who claim that the GPL license text and the offer of the source must be in every distribution, ie. in comments in every JS module, but most people think that is going a little far and would bring the net to a grinding halt.

Answer 2

AFAIK, you have to keep the GNU disclaimer in your javascript as well.

EDIT: In fact, there's an interesting parapraph in gnu.org, saying you would need just a notice like this:

Copyright (C) YYYY  Developer
The JavaScript code in this page is free software: you can
redistribute it and/or modify it under the terms of the GNU
General Public License (GNU GPL) as published by the Free Software
Foundation, either version 3 of the License, or (at your option)
any later version.  The code is distributed WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

As additional permission under GNU GPL version 3 section 7, you may distribute non-source (e.g., minimized or compacted) forms of that code without the copy of the GNU GPL normally required by section 4, provided you include this license notice and a URL through which recipients can access the Corresponding Source.

Check the GNU link for more information, it's a great resource.