Some sites use server side generation of scripts using other programming languages such as PHP or PERL to deliver the script when called upon but again this is very weak as the very nature of the script requires that the script is available to browser in a native fashion and hence is easily readable by using, say, the “Save As” option on a page. This will simply request the page content and place in all in a file, including client-side scripts.
In my experience, assuming that your scripts work well they should be documented, a GNU license and copyright stated in the hope that, if used, some credit will be given if not a commission for commercial work. In our commercial dealings we use obfuscation however always in the knowledge that this is only a deterrent but it the best we can currently achieve.
Jasob 3 (2010) JacaScript Obfucsation [Online]. Available at http://www.jasob.com/ (Accessed 26 September 2010).