Copyright issues with combining JavaScript files?

Question

Say my web application uses jQuery, and I combine jQuery's source file with my own JavaScript files into a single file.

Now, I still have to put jQuery's copyright header at the top of the combined file, right? But do I also have to add a notice that I "modified" this file as I have added my own code?

What if I'm using multiple JavaScript libraries and have combined all of them, as well as my own code, into a single file? Do I dump all their copyright headers at the top and add a modification notice? Would it be legal?

And a related question, do I have to also include a copy of all the related licenses in my website? If so, how are major websites handling this? For example, StackOverflow uses jQuery, where is its page containing the MIT or GPLv2 license?

Answer 1

I have no idea of the legal issues, but accepted practice is to put a copyright comment block before each piece of open source code. At flickr we use YUI, and put this block before includes YUI code in our combined files:

/*
Copyright (c) 2010, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.com/yui/license.html
version: 3.3.0
build: 3167
*/

As you can see it includes a link to the license, copyright information and a description of the license.