All the scripts that I have seen, disable access to the browser context menu that is activated by a right-click. The main objective is to prevent the users from selecting the ‘View Page Source’ option in the context menu. But many people do not realise that the page source can be viewed by other means.
In Firefox, the keyboard shortcut,
Ctrl-U, will open the page source window. Alternatively, there is also a ‘Page Source’ option under the ‘View’ menu in Firefox.