In order for the software to be Free, just having the source code is not enough. You need to have a copyright license that gives each user the <a href="https://www.gnu.org/philosophy/free-sw.html">4 essential freedoms</a>. JavaScript are little software elements running inside webpages automatically as you load the page. And they might or might not have a Free Software license. On the other hand, companies like to mangle the JavaScript programs enough, so no human reader could ever understand them. Resulting in something similar to a binary program. You can read more about this issue in an article <a href="https://www.gnu.org/philosophy/javascript-trap.html">"The JavaScript Trap"</a> by Richard Stallman.